Hypermesh Book 6o6o21

[email protected]

/scripts/hm. o Set up an alias.

HyperWorks 13.0

HMD Introduction 9 Proprietary Information of Altair Engineering, Inc.

Chapter 1: Basics HyperMesh Desktop



Mac OS X: The HyperWorks Mac OS X applications can be invoked as follows. o

The icons in the Applications Menu under the default location (if defaults were used) or the chosen install folder location.

o

The install location under scripts via a terminal window. (For example, the command /Applications/AltairHyperWorks/altair/scripts/hm under a terminal window would launch HyperMesh.)

The Start-In Directory The “Start-In Directory” or “Working Directory” is the location from which the HyperWorks Desktop application is launched. This directory defines where certain settings files are written by default, and where customization files will be searched. 

Configuration files (hmmenu.set, hmsettings.tcl, hwsettings.xml, hm.mac, etc.)



History File (command.cmf)



HyperMesh Model Files, FE Data and Geometry Files. ( can browse to different directories for opening and saving)

The file browser will also use this directory as its default location for browsing for files. This can be considered as the "current working directory". This directory can be changed, thereby changing the location where these files are written to or read from. This has the benefit of allowing different settings to be stored in different directories to give control over the HyperWorks Desktop environment for different projects or use cases.

10 HMD Introduction

HyperWorks 13.0 Proprietary Information of Altair Engineering, Inc


Changing the Start-in Directory on Windows On Windows, the default start-in directory for HyperWorks is the My Documents directory. This can be changed by editing the "Start in" field on the application executable or its shortcut. 1. Locate and right-click the relevant HyperWorks Desktop application icon from the Start menu Altair HyperWorks group. Or Locate and right-click the HyperWorks Desktop executable file (e.g. \hw.exe) 2. Select Properties to open the properties dialog. 3. Select the Shortcut tab. 4. Edit the Start in field to contain the path to the directory in which you want to run the HyperWorks Desktop application. This directory becomes the start-in directory. 5. Click OK. 6. Start the HyperWorks Desktop application as defined in the "Starting HyperWorks Desktop Applications" section.

Changing the Start-in Directory on Linux On Linux, the start-in directory is defined by the directory from which the runs the application startup script. 1. cd to the directory in which you want to run the HyperWorks Desktop application.

Start the HyperWorks Desktop application as defined in the "Starting HyperWorks Desktop Applications" section.

HyperWorks 13.0



Settings Files HyperWorks Desktop writes several different settings files. HyperMesh writes command.cmf, hmmenu.set and hmsettings.tcl. HyperWorks Desktop writes hwsettings.xml. Each of these files is detailed below.

command.cmf The command.cmf file is a command history file containing the commands executed in HyperMesh whenever any operation is performed. This file can be used to rerun operations or as a basis for determining the commands required to automate a given process. The command.cmf file is written to the start-in directory for each session. Deleting this file simply results in a new file being created on the next operation.

hmmenu.set The hmmenu.set file stores information about options, settings, profiles, graphics settings, element check settings, penetration check settings, and several other settings. The hmmenu.set file is written to the start-in directory after each session is closed. Deleting this file resets the stored settings to their default values. It is possible to customize the location where this file is read from during start-up. HyperWorks Desktop uses the following search order to find the hmmenu.set file. If copies exist in multiple locations, only the first one found in the search order is used: 1. Start-in directory 2. Home directory 3. HW_CONFIG_PATH environment variable 4. Installation directory

12 HMD Introduction



hmsetting.tcl The hmsettings.tcl file stores information on the browsers, the interface layout (tab locations, command window, location, toolbars, etc...), keyboard preferences, import/export settings, recent files, and other various settings. By default, the hmsettings.tcl file is written to the My Documents directory on Windows and in ~/.altair on Linux after each session is closed. Deleting this file resets the stored settings to their default values. It is possible to customize the location where this file is read from during start-up and written to on exit. HyperWorks Desktop always writes the hmsettings.tcl file back out to the location where it originally read it from for that session. The following order is used to find the hmsettings.tcl file: 1. HM_SETTINGS_DIR environment variable. If this is defined, the search stops even if the file doesn't exist. 2. My Documents directory on Windows or ~/.altair on Linux

hwsetting.xml The hwsettings.xml file stores information on the browsers, the interface layout (tab locations, command window, location, toolbars, etc...), keyboard preferences, import/export settings, recent files, and other various settings. By default, the hwsettings.xml file is written to the My Documents directory on Windows and in ~/.altair on Linux after each session is closed. Deleting this file resets the stored settings to their default values. It is possible to customize the location where this file is read from during start-up and written to on exit. HyperWorks Desktop always writes the hwsettings.xml file back out to the location where it originally read it from for that session. The following order is used to find the hwsettings.xml file: 1. HW_SETTINGS_DIR environment variable. If this is defined, the search stops even if the file doesn't exist. 2. My Documents directory on Windows or ~/.altair on Linux

HyperWorks 13.0



Online Help HyperMesh offers comprehensive documentation in the online help. The Help can be accessed through the menu bar or the use of the “h” key on your keyboard. If the accesses help through the use of the “h” key, the help documentation is “intelligent”, opening in the section representing the that the is actively in. Help also contains detailed tutorials on many advanced HyperMesh functions.

14 HMD Introduction


Chapter 1: Basics HyperMesh Desktop Example: how to use HyperWorks Online Help to search documentation about comments created by HyperMesh in the input deck.

HyperWorks 13.0



HyperMesh Desktop Graphical Interface

Title Bar – It tells you which product is active Menu Bar – It enables access to many types of functionality. It places functionality into groups, accessible via pull downs Toolbar – It gives access to commonly used tools via icons Browser – contains the following tabs: •

Solver, Model, Utility, Include, Import, Export, Connector, Entity State, Entity Editor, etc.

Graphics area – displays the model Menu Pages – divides the main menu into groups based on function area – menu items / functions for interacting with HyperMesh Sub-s – divides into similar tasks related to ’s main function Command Window – lets the type in and execute tcl commands •

Available through the View drop down menu (turned off by default)

Status Bar – shows status of operations being performed •

Indicates the “current” Include file, Component Collector, and Load Collector

16 HMD Introduction



HyperMesh Desktop Clients HyperWorks applications can be selected from the Client Selector toolbar. The Client Selector button on the left-most end of the toolbar allows you to select HyperMesh, HyperView, HyperGraph 2D, HyperGraph 3D, MediaView, and TextView. The toolbars, view controls, and menu bars change based on the application you select.

HyperMesh Desktop Keyboard Shortcut and Setting The secondary menu is a list of s that can be accessed by using the function keys F1 through F12, or in combination with the SHIFT or CTRL keys.

HyperWorks 13.0



2 - Opening and Saving Files Bringing data files into HyperMesh and saving them are frequent operations every should understand. This section will help you become proficient with the various ways this can be done in HyperMesh. The remaining exercises in this course will assume you know how to open and save files in HyperMesh. In this section, you will learn how to: 

Open a HyperMesh file



Import a file into a current HyperMesh session



Save the HyperMesh session as a HyperMesh model file



Export all the geometry to an IGES file



Export all the FE data to a OptiStruct Analysis input file



Delete all data from the current HyperMesh session



Import an IGES file



Import a OptiStruct Analysis file to the current HyperMesh session

File Operations The following file operations are located in the Standard toolbar which can be accessed by selecting View > Toolbars > HyperWorks > Standard.

18 HMD Introduction



HyperWorks 13.0



20 HMD Introduction



3 - Controlling the Display When performing finite element modeling and analysis setup, it is important to be able to view the model from different vantage points and control the visibility of entities. You may need to rotate the model to understand the shape, zoom in to view details more closely, or hide specific parts of the model so other parts can be seen. Sometimes a shaded visualization is best, while other times wireframe visualization is needed to work on details inside the model. HyperMesh has many functions to help you control the view, visibility, and visualization of entities. This section introduces you to these functions. In this section, you will learn how to: 

Control the points of view, mouse, and toolbar.



Control the visibility of entities using the Mask .



Control how entities look by using toolbars and the Model Browser.



Rename components.



Identify and delete empty components.



Delete all the geometry lines.

View Control View control is accomplished through the use of the Standard Views toolbar icons, and 3D View Controls toolbar, and the mouse. 

Standard Views Toolbar Icons

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

3D View Controls Toolbar Icons

22 HMD Introduction


Chapter 1: Basics HyperMesh Desktop From pull down menu Preferences > Geometry Options or click “o” from keyboard, you can manage the rotate angle and the zoom factor linked to the previous buttons.



Mouse Controls – The preferred method for Display Control is the use of the Mouse Buttons. With the CTRL key held on the keyboard the mouse provides total control over rotation, zoom and pan.

HyperWorks 13.0



Model Visualization



Various surface shading options are available on the Toolbar:

From pull down menu Preferences > Geometry Options or click on “o” from keyboard.

24 HMD Introduction


Chapter 1: Basics HyperMesh Desktop 

Transparency

Transparency is available from the Toolbar, allows surface shading in a component to be set to any level of transparency (Viewing the midsurface of solid geometry).



Various FEM shading options are available on the Toolbar:

HyperWorks 13.0



See the pull down menu Preferences > Meshing Options or click “o” from keyboard, to get more details.

26 HMD Introduction



Display Toolbars Display Toolbar The display and masking tools allow the to show and hide select entities that might interfere with the desired visualization. The icons can be found on the Display toolbar and are used as follows:

Spherical Clipping The Spherical Clipping allows you to focus on specific areas of the model by displaying only the portions of a model inside a 3D spherical volume, while masking everything outside the sphere. If you want to work on a small section of a large model without masking or turning off any entities, enable the clipping and pick the center and the radius of the clipping sphere. It can be accessed using the icon shown below.

HyperWorks 13.0

and will open the



Browsers •

Browsers display information in a tree view; collectors such as components or groups appear at the top level of the hierarchy, while collected entities such as elements or surfaces display as "children" nested within the collector to which they belong.

•

Different browsers are customized for usage with regard to the types of parts that you want to work with.

•

Most browsers have similar basic functionality for sorting entities, filtering entities, and finding entities and include a context-sensitive right-click menu and sets of control buttons.

28 HMD Introduction



The Selector is a tool to interactively select any type of ed entity via the browser, or by selecting within the graphics area.

Model View The Model View ( ) resides on the Model Browser and allows you to view the model structure while providing full find, display, and editing control of entities. The model structure is viewed as a flat, listed tree structure within the browser. However, if the model has an assembly hierarchy then the Model Browser accommodates this hierarchical structure. The browser can list every named entity within the session and places those entities into their respective folders; however, it does not non-named entities such as nodes and elements. Some of the more important entities within the model include: assemblies, components, multibodies, properties, materials, entity sets, groups, load collectors, system collectors, vector collectors, and beamsectcols -- all of which are placed into a tree-like display. To open the Model View, click the Model item located within the View menu. The browser displays on one of the tab area sidebars. The Model View is a powerful tool for controlling the visualization of the model. In the Model Browser the can: 

Complete Listing of all HyperMesh Entities in Model



Each “Collector” is expandable and lists all contained “Entities”



Turn on and off the display of the geometry



Control the color of the collector (Right click)

and elements

HyperWorks 13.0

of collectors





Create, Card Edit, Delete and control component visualization by Right clicking on the collector list

Component View (

)



Lists All Components in Model



Colors Model “by Component”



Quickly Sort by Name, ID, Color, or Property



Display State Icons (Geometry and FE: ON/OFF Single Picking)



Global Controls to Operate on all Components (All, None, Reverse)



Browser Modes (Graphics/Browser List Picking for: Select, Show/Hide, Isolate)

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Mask View

HyperWorks 13.0



4 - Working with s Much of the functionality in HyperMesh is centered around the use of s. While there are often many ways to get to a function within HyperMesh, most often the actions lead the to the area to select entities, enter values and execute functions. The area is split into seven pages and on each page are s that allow the to utilize all of the functionality in HyperMesh. Even if the accesses a function through the use of the menu bar or the toolbars, much of the information will be entered in the area. While this manual cannot explain the functionality of every , much of the functionality is common amongst all of the s and thus learning one will assist the in the use of all s. This section introduces you to common attributes and controls as it guides you through translating nodes and elements using the Translate and measuring distances between nodes using the Distance . In this section, you will learn how to: 

Use the entity selector and the extended entity selection menu to select/unselect nodes and elements from the graphics area



Use the direction selector to define vectors along which to translate nodes and elements



Switch between different entities to select and methods to define vectors



Toggle between two options



Enter, copy/paste and calculate numbers



Use the rapid menu functionality to execute commands with the mouse buttons rather than clicking buttons



Interrupt, but not exit, a to go to another using the keyboard function keys

Layout In HyperMesh, s have three general layouts. The Basic , with Sub-s and s with Sub s organized in Columns. Their look and functionality will be described below. 

The Basic

Translate

32 HMD Introduction





with Sub-s

Project/to plane



with Sub-s as icons

Surfaces



with Sub- and Columns

Surface Edit/trim with nodes sub

Generally s are used in a left to right manner and those with columns are used in a left to right and top to bottom manner using the following steps:

HyperWorks 13.0



Step 1: “What to Do” This step only applies to s with subs. The picks the functionality within the that is desired by picking the appropriate sub radio button. The example below to the left is from the Project and the “to plane” sub functionality is chosen. The example below to the right is from the Surfaces and the “square” sub function is chosen.

Step 2: “Method to Use” This step only applies to s with subs that are organized in columns. Often, subs are organized into different columns when there are more than 7 sub options. The column organization groups like functionality together in instances where the entire is not needed for information entry. In this case the picks the sub in Step 1 and then chooses the method they wish to use within that sub and follows the column top to bottom. The example below shows the Surface Edit with the “trim with surfs/plane” sub functionality chosen. You can see the three columns providing access to either the “with plane”, “with surfs” or “self-intersecting surfs” options.

Surface Edit/trim with surfs/planes sub

Step 3: “What to do it to” In this step the will select the entities they wish to perform the function on. The entity selection is shown below.

34 HMD Introduction


Chapter 1: Basics HyperMesh Desktop Step 4: “How to do it” In this step the defines parameters that dictate how the function will be performed.

Step 5: “Do the action” Clicking the green “action” button performs the desired function while the “reject” button will reject the last performed function.

Tools within the s Within the s there are many buttons and options that will be explained below: Switches These allow the choice of multiple options through a popup menu Toggles The toggle will change the function between 2 options. Reset This will reset the selection of any entities. Text input fields Operate like text fields in most programs Extended Selection Clicking the yellow selection button will open the extended selection window. This provides numerous tools allowing for the advanced selection of entities.

HyperWorks 13.0



Direction/Plane Selection 

X, Y, Z Axis -



N1, N2 and N3 o

Select 2 Nodes (N1 & N2) – This defines a direction from N1 to N2 where a vector type direction is required. When a plane is required the plane is defined as that which is normal to the vector N1 to N2 and its location at the B node.

o

Select 3 Nodes (N1, N2 and N3) – This defines a plane whose normal defines a direction when a vector direction is required. Positive of the normal is defined by the “Right Hand Rule.” In the event a plane is required the plane is that which is created by the 3 nodes with its location at the B node.

36 HMD Introduction



5 - Organizing a Model Organizing model data can be beneficial when creating a valid solver input file. Basic tasks used to organize model data such as placing elements and loads into groups (collectors), organizing collectors into assemblies, renaming, deleting, reordering, and renumbering are discussed in this section. In this section, you will learn how to: 

Create geometry and organize it into components



Organize elements into components



Rename components



Identify and delete empty components



Delete all the geometry lines



Reorder the components in a specific order



Renumber all the components, starting with ID 1 and incrementing by 1



Create an assembly



Organize the constraints

Model organization is at the heart of a quality Finite Element Analysis. The model can be organized in a multitude of different ways as desired by the , but below are the basics for model organization.

HyperWorks 13.0



Collectors The basis for model organization is the collector. HyperMesh has many different types of collectors:

*NOTE: Property and Material collectors do not “contain” any entities and are used to define material and physical properties in the model. They are called collectors for uniformity.

Collectors can be created in a number of ways. 



HyperMesh Model Browser: 

Right clicking in the Model Browser opens a menu from which the selection of Create allows for creation of any type of collector.



Right clicking in the Model Browser will also allow you to edit, rename, change ID, change color and delete collectors as well.

Pull down Menus Selecting the Collectors Pull-Down and then selecting Create will provide the ability to create any of the non-property collectors.

38 HMD Introduction



Material and Property Collectors can be created in a similar manner using the Material and Property Pull-Downs.



Collectors Toolbar The Icons can be used to create collectors as well.

HyperWorks 13.0





Favourite Toolbar

Model Organization – Model Browser Model Browser: •

View collectors and assemblies in a hierarchical tree format

•

Create, delete, and rename collectors

•

Edit collector attributes

•

Organize collectors into assemblies (Drag and drop)

•

Also available using the Collectors icon

40 HMD Introduction



Model Organization – Model Browser & Current Collector The Current Collector determines what collector new entities are placed in. The Current Collector can be determined in two ways: Model View or Status Bar. Using the Model View: 

In the Model View the Current collector will be in BOLD



Note the mid2 collector is in a bold font and thus is the Current collector.



Right clicking on a collector will open a menu that will allow it to be made current.

Using the Status Bar: 

In the Status Bar click on the Set Current Component field and select the one you want to male current from the list that appears in the area.

HyperWorks 13.0



Model Organization – Model Browser & Entity Editor Create the entities needed for your model using Model browser + Entity Editor.

42 HMD Introduction



Model Organization – Reference Browser New entities are created in the current collector: References represented by the icon correspond to entities that are referenced by the specified entity. Cross-references represented by the icon correspond to entities that reference the specified entity.

For example, in the case of a component, Cross-references would list the groups, sets, output blocks, etc that refer to the selected component. In addition, only for components, Cross-reference will have sub folders named Node and Element and will list the entities where the selected component’s node or element is referred.

Organize Organize is a tool that can be used to move/copy entities to different collectors. It can be accessed using the icon open the shown below.

or from pull down menu View > Organize and will

HyperWorks 13.0



Renumber The Renumber allows you to renumber entities. You may also enter a value by which to offset the IDs of entities. It can be accessed using the icon will open the shown below.

or from pull down menu View > Renumber and

Delete The Delete allows you to delete data from a model database; preview and delete empty collectors; preview and delete unused collectors (property, material, curves). You can also delete an entire model database, if you wish to start with a clean database. It can be accessed using the icon

or (F2) and will open the shown below.

Nodes The Nodes allows you to create nodes using a wide variety of methods.It can be accessed from pull down menu Geometry > Create > Nodes or (F8) and will open the shown below.

44 HMD Introduction



Temp Nodes The Temp Nodes provides a way to control which nodes are on the temporary node mark. Since all nodes not currently referenced in the model are deleted, the temporary node mark is provided as a holding area to save the nodes you are not currently using. It can be accessed using the icon from pull down menu Geometry > Create > Nodes > Temp Nodes or (Shift+F2)

this will open the shown below.

Distance The Distance allows you to determine the distance between two nodes/points or the angle between three nodes/points, or to change distances or angles. It can be accessed (F4) and will open the shown below.

HyperWorks 13.0



Exercise 1a - Interacting With HyperMesh Desktop This exercise will cover many of the basic concepts that are central to many of the features in HyperMesh Desktop. By the end of this exercise you should be familiar with the basic features of the HyperMesh Desktop software.

Step 1: Set the Profile and retrieve the model file, 01-GUI.hm 3. From the menu bar, select Preferences > Profiles or select the icon

.

4. Select the OptiStruct profile. 5. Click OK. 6. Select File > Open > Model from the menu bar or select the icon

.

7. Select the file 01a-GUI.hm. 8. Click Open

Step 2: Rotate, Pan and Zoom the model 1. Hold down the CTRL key 2. Click the LEFT Mouse button. (Note the small square in the center of the screen indicating the rotational center). 3. While holding both the CTRL Key and LEFT Mouse Button, drag your mouse around to rotate the model. 4. Click near a node (Note the small square moves to the node selected and becomes the new center of rotation). Continue to rotate the model. 46 HMD Introduction



5. While holding the CTRL Key and the RIGHT Mouse Button, drag your mouse around to pan the model. 6. While holding the CTRL Key, click the Center Mouse Button (or clickable scroll wheel) and draw a circle around a portion of the screen.

7. This will zoom into the region surrounded by the drawn circle.

8. While holding the CTRL Key rotate the scroll wheel forward to Zoom Out and backward to Zoom In. 9. While holding the CTRL Key click the middle mouse button/scroll wheel to “fit” the model to the screen.

HyperWorks 13.0



Step 3: Use the Model Browser to control visualization 1. Press F on the keyboard to “fit” the model to the screen. If it does not work, click in the graphics window and then press F. 2. Make sure the Model Browser tab > Model View icon

is active.

3. Expand the Component category by clicking the + next to it. This will list all of the components in the model. 4. Using the Geometry

and Elements

Icons, turn on and off components.

48 HMD Introduction



Using the Show/Hide Button turn off and on components in the graphics window. Right click to hide a component and left click in the area of a hidden component to see a ghost image of the hidden component. Releasing the button reveals the component.

5. Using the Isolate Button , right click on a component in the graphics window to isolate it (turn off all other components) and left click on a hidden component to see a ghost image of the hidden component. Releasing the button isolates the selected component. 6. Use the global controls

to turn on, off and reverse all of the components.

7. Highlight components using the Left Mouse Button in the Graphics Area, and note how the Global Controls now only affect the highlighted components. 8. Use the icon ( Both options.

) to switch the global controls between the Geometry, Elements and

9. Review the other Model Browser Views: a.

Component View This view is highly useful when working solely with components as none of the other collectors are shown in the view. This view contains all of the visibility control and right click functions of the Model View. Additionally it adds fields that show the mesh and geometry shading as well as the property and material applied to each component.

HyperWorks 13.0



b.

Property View This view allows the to view all of the properties in the model and color the entities on the screen by their assigned property. The visibility controls as well as all right click extended functionality work with this view as well.

c.

Material View This view allows the to view all of the materials in the model and color the entities on the screen by their assigned material. The visibility controls as well as all right click extended functionality work with this view as well.

50 HMD Introduction


Chapter 1: Basics HyperMesh Desktop 10. Context-Sensitive Menu - You can change a variety of options by right-clicking on a folder or entity in the browser's tree display. Options you specify in empty space around the model apply to the entire model. 11. Right click on the “Component” folder will open the following context menu.

Try the following functions: a. Create a new component

HyperWorks 13.0



b. Rename a component Left Click on the new component “component1” will open below the “Entity Editor” tab area, where you can change component name in the Value field.

c. Select the color, in a component row, and change the color of a component.

52 HMD Introduction


Chapter 1: Basics HyperMesh Desktop d. Show/Hide & Isolate a component

e. Isolate Only a component (see if you can figure out the difference between Isolate and Isolate Only) f.

Delete a component

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Step 4: Working with Collectors 1. Right click on the in the Model tab > Model View > “Component” folder will open the following context menu, select Create.

2. Left Click on the new component “component1” will open below the “Entity Editor” tab area, where you can change component name in the Value field.

3. In the Entity Editor, Name it Bucket and select a color.

54 HMD Introduction


Chapter 1: Basics HyperMesh Desktop The new collector has been created and now we will move the elements for the bucket into this new collector. 4. From the menu bar select Mesh > Organize > Elements > To Component or select the icon

.

5. In the Model Browser click the Selector Icon from the graphics window.

. This allows you to pick components

6. Click the bucket in the graphics window, component “Scuaufel-GEOM-2D”

7. Click the Add To Collector icon . This will add the selected elements, included in “Scuaufel-GEOM-2D” component, to the selection. 8. Click the dest component= button and select the newly created Bucket component. 9. Click move and the elements in the collector will be moved to the new component.

Step 5: Use of s and Directional Functions This step will introduce the to commonly used functions in s as well as the use of the directional definition tools found in many HyperMesh s. 1. Locate the item in the menu bar that allows you to Translate Elements (Mesh > Translate > Elements).

HyperWorks 13.0



2. Select the elements included in the component -GEOM-3D.

3. From the direction definition switch select N1, N2, N3.

X,Y and Z axis will translate along those cardinal axis, while N1,N2,N3 allows the to define a direction as a vector (N1->N2) or as a normal to a plane defined by the points N1,N2 and N3 following the right hand rule. 4. Pick a node on the flat face of the -GEOM-3D component shown below. A green dot will appear at the selected node showing that N1 has been defined there. The blue focus square will automatically move to N2.

5. Continue in a Clockwise direction picking two more nodes on the face defining the blue N2 and red N3 nodes. Your model should look similar to the picture to the right. NOTE: It is not necessary that your nodes be identical to the image, just similar.

56 HMD Introduction


Chapter 1: Basics HyperMesh Desktop 6. Enter 30 in the magnitude= field 7. Click translate -. The entire component will move 30 model units in the negative direction defined by the normal of the plane N1, N2 and N3.

8. Click reject. 9. Try moving the component in other directions using both cardinal axis and the N1, N2 and N3 options. 10. Try moving the component using only N1 and N2 and then change the magnitude= field to N2-N1 and see what that option does. 11. Use the reject button and the opposite direction translation to bring your component back to the previous location.

Step 6: Using the Mask Function and Selecting Entities 1. Using the Mask Icon

from the Display toolbar to enter the Mask .

2. Change the entity selection to elems. 3. Pick a number of elements on the screen.

HyperWorks 13.0



4. Click mask. This will hide the elements from view but they still can be affected through other s.

5. Click the Reverse Icon

.

This will Unmask the hidden elements and will mask all the elements previously shown.

6. Click the Unmask Adjacent Icon

.

58 HMD Introduction


Chapter 1: Basics HyperMesh Desktop This will unmask elements immediately adjacent to those on the screen. This can be done repeatedly.

7. Click the Unmask All Icon

to bring everything into view.

8. Click the Mask Icon again. 9. Hold the Shift Key down and holding the Left Mouse Button, drag a box in the graphics window to box select elements.

10. Hold the Shift Key down and holding the Right Mouse Button, drag a box in the graphics window to de-select elements. 11. Click the yellow elems button to open the extended selection window.

HyperWorks 13.0



12. Experiment with options, including the following: 

displayed – Selects entities currently displayed on the screen



all – Selects ALL entities in the model, displayed or not.



reverse – After selecting a few elements this will “reverse” the selection.



by collector – Displays a list of collectors and entities can be selected by the collector they are in.



by geoms – By choosing either surfs or solids, elements can be selected by picking the geometry that they were created from. Useful in that a single geometry selection can select many elements.



save/retrieve – Saving a selection places those entities into a 1 slot “ mark” that can be retrieved again and again in selections until it is overwritten.

60 HMD Introduction


Chapter 2: Geometry

Chapter 2

Geometry 1 - Importing, Exporting and Repairing CAD HyperMesh is capable of importing geometry from many CAD sources. Most of the popular CAD packages are read directly, and for those that are not, HyperMesh s the popular intermediate languages. HyperMesh attempts to properly clean up surfaces during import and offers a wide variety of tools to remedy these geometric issues. The benefits of importing and repairing CAD are: 

Restore the surface data of the part (unconnected, missing and duplicate surfaces)



Create the simplified part needed for the analysis



Mesh a part all at once



Ensure proper mesh connectivity



Obtain a desirable mesh pattern & quality

In this section, you will: 

Delete untrimmed surfaces



Close missing surfaces



Set the cleanup tolerance



Equivalence free edges



Delete duplicate surfaces

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Chapter 2: Geometry

Geometry Import Importing geometry occurs in the Import tab, which is accessible through the Import Geometry Icon

or from File > Import > Geometry (drop down menu).

Using this tab the can import data from popular CAD packages such as: 



Unigraphics (NX6, NX7, NX7.5, NX8, NX8.5, NX9.0) o

UG Part Browser

o

s import of *.prt, *.asm files

o

Provides a UG part browser

o

Requires an installation of UG to be accessible, either locally or on a network

CATIA (V4, V5 R23 & V5-6R2013) o

CATIA V4 (*.model and *.exp)

o

CATIA V5 Altair license feature required to import V5 files (*.CatProduct, *.CatPart and *.cgr)

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

Pro/Engineer (Wildfire 5.0, Creo 2, M060) o

s import of .prt and .asm files.

Additionally HyperMesh s the import of the following intermediate translational languages: 

STEP (AP203, AP214) o

s import of *.stp files



IGES (v6, JAMA-IS) o s Import of *.igs, *.iges files



Parasolid (v26 (native); v20 (third-party)) JT (10.1) SolidWorks (2013) DXF, ACIS, FiberSim, PDGS, Tribon, VDAFS

  

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Chapter 2: Geometry

Geometry Export Exporting geometry occurs in the export tab which is accessible through the Export Geometry Icon

or from File > Export > Geometry (drop down menu).

Using this tab the can export data in the following format: 

PARASOLID (V9)



IGES (v6, & JAMA-IS)



STEP (AP214)

…

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Chapter 2: Geometry

Topology Repair Surface Definition

What is “Topology” Topology is how surfaces are connected to adjacent surfaces of a part. 

Surface connectivity is controlled by the associated surface edges



If a surface edge is associated with more than 1 surface, those surfaces are considered to be connected (“equivalenced”)



Surface edges are categorized, named, and colored according to the number of associated surfaces

Connectivity is really important and critical at the same time, when you need to create a contiguous mesh over connected faces thus guaranteeing stresses, strains and deformations that will propagate over the part in a realistic manner. HyperMesh uses a tolerance calculation to determine when two or more edges should be connected and provide tools to fix connectivity issues before meshing. HyperMesh allows easy visualization of surface connectivity through the use of an edge color scheme shown below:

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Chapter 2: Geometry

Topology Visualization

In the HyperMesh Visualization toolbar, the Visualization Options Icon Visualization tab > Topology icon

will open the

.

This tab will allow the to: 

Display or hide 2D and 3D topology (free, shared, t-junctions, suppressed edges) based on its type



Control surface transparency



Display 3D mappability with different shading colors related to Mappable solid regions.

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Other functionality in this tab: Connector Constraints Equations Loads Morphing Systems Vectors Topology display mode is a default for some s (surface edit, quick edit, point edit, edge edit, autocleanup, and automesh). Display of the topology can be controlled with the Geometry Color Mode icon included in the HyperMesh Visualization toolbar.

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Chapter 2: Geometry

Topology Repair: General Process HyperMesh will in most cases create proper and connected geometry accurately representing the initial CAD geometry. In some cases you need to work with topology to repair geometry. The general process is the following: 

Figure out what the ideal surface connectivity of the part should be.



Observe the current display of topology colors (free, shared, t-junction). Figure out what is causing the topology to be displayed this way.



Use the tools in HyperMesh that get the connectivity from what it is to what it should be as quickly and efficiently as possible.

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Topology Repair: Tools HyperMesh has a supply of tools to repair issues in the geometry. Below you can find the tools that HyperMesh provides: 

Quick Edit (Geometry > Quick Edit or F11)

The Quick Edit is a “tool box” of utilities for geometry repair. Many of the tools can be found in other s and their functionality is exactly the same. The Quick Edit simply provides a single location for many of the most often used tools. These include: o

Split surf-node  Divides a surface by cutting in a straight line between 2 selected nodes

o

Split surf-line  Divides a surface by cutting in a straight line between a node normal to selected line.

o

Washer split  Adds a circular edge around a hole in a surface (Mostly used for creating all quad mesh around a hole)

o

Unsplit  Removes / deletes an edge created by splitting a surface in HyperMesh

o

Toggle  Change edge type within tolerance

o

Filler Surf  Select a line on a free surface edge to recreate any missing surfaces

o

Delete Surf  Delete selected surface(s)

o

Adjust/Set Density Allows to interactively change mesh node density along selected edges

o

Replace point Moves/retains points

o

Add/Remove Point Creates/Deletes a fixed point at the selected locations

o

Add point on line Creates a specified number of fixed points along the selected edge

o

Release Point Disassociates the selected fixed point from all the connected edges

o

Project point Projects free points to existing surfaces or lines

o

Trim-intersect Removes the edge fillets

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Chapter 2: Geometry





Edge Edit (Geometry > Edit > Surface Edges)

o

Toggle > (2 edges pair at a time) toggles edges from one state to another (free > shared > suppressed, by clicking with the left mouse button) based on the cleanup tolerance setting.

o

(Un)Suppress  Selects multiple edges to suppress, all of them at once

o

Replace > (1 edge pair at a time) combines two edges into a shared edge at the location of one of the original edges, controlling which edge to retain and which to move.

o

Equivalence > (multiple edges at a time) searches for free edges and combine them with a matching edge within the cleanup tolerance.

o

Unsplit > removes previously created split-lines

o

Edge fillets > removes fillets from surface edges.

o

By feature > combines surfaces based on geometric features (angle surfs and offset surfs )

Point Edit (Geometry > Edit > Fixed Points)

o

Add > Adds new points to the model geometry to help control mesh pattern (especially helpful along edges to control node seeding)

o

Suppress > "Turn off" points in the model geometry. The points are not deleted, they are ignored when meshing.

o

Replace > Combines 2 fixed points together at a single location; moves one point to another, combining them into a single point.

o

Release > Use this to "release" vertices so that they become free (unattached points) and any shared (green) edges that they were attached to the point become free (red) edges.

o

Project > Projects fixed points onto a nearby edge (Useful for aligning mesh between 2 edges).

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

Surface (Geometry > Create > Surfaces > Spline/Filler)

o

Spline/Filler ( ): Creates surfaces by filling in gaps, such as a hole in an existing surface. The Keep tangency option is valid for surface edge line selection only. It considers curvature of any surfaces attached to the selected edges and tries to create a surface tangent to them. This helps to form a smooth transition to the surrounding surfaces. The Auto create (free edges only) option is valid for free surface edge line selection only. It simplifies the selection of the lines bounding the missing surface. Once a line is selected, HyperMesh automatically selects the remaining free edges that form a closed loop, and then create the filler surface.

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Chapter 2: Geometry

Exercise 2a - Loading and Repairing CAD Geometry This exercise uses the model file, 02a-TOPOLOGY-REPAIR.hm.

Step 1: Open the model file, 02-TOPOLOGY-REPAIR.hm. Step 2: View the model in topology display toolbar to evaluate its integrity. 1. Observe where the model has incorrect connectivity and missing or duplicate surfaces. 2. Click Geometry > Quick Edit to open the Quick Geometry Edit . Note that the surface edges are now colored according to their topology status. This occurs because Geometry Color is set to Auto (

3. Click Wireframe Geometry (

).

) to display the model in Wireframe mode.

The toolbar contains icons that control the display of the surfaces and surface edges. Surfaces can be shaded with or without edges or wireframe. Place your mouse over the cursor to view a description of the button’s functionality and select the icon drop-down menu for additional options.

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4. Click Visualization (

) and navigate to the Visualization tab > Topology icon.

Visualization controls the display of the surfaces and surface edges. Surfaces can be shaded or wireframe. The check boxes within this menu turn the display of the different edge types and fixed points (surface vertices) on or off. 5. Clear all the check boxes except the Free check box. Only the free edges should be displayed at this point. 6. Observe the free edges and make note of where they are. The free (red) edges show where there is incorrect connectivity or gaps. 7. Note the locations where there are closed loops of free edges. These are locations that probably have missing surfaces.

Free edges indicating surface discontinuities of the clip geometry

8. Select only the Non-manifold check box. 9. Observe the non-manifold edges and make note of where they are. The non-manifold edges show where there are more than two surfaces sharing an edge, which might indicate incorrect connectivity or correct T-Connections. For this part, there are no yellow edges. This indicates that there are not duplicate surfaces or Tconnection. 10. Select all the check boxes. 11. Click the Close button to close the Visualization tab. 12. Click Shaded Geometry and Surface Edges (

)

The surfaces should now appear solid rather than having only their edges displayed.

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13. Rotate, zoom, and pan to locate any errors in the geometry. 14. Make note of the areas to be worked on:  A surface that overhangs a round corner  A missing surface

Surface overhanging an edge and a missing surface

Step 3: Delete the surface that overhangs the round corner. 1. Enter the Delete in one of the following ways: 

From the menu bar click Geometry > Quick Edit > delete surf

OR  From the menu bar click Geometry > Delete > Surfaces OR  Press F2

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2. In the graphics area, select the overhanging surface shown in the picture below. From the menu bar click Geometry > Quick Edit > delete surf

3. This will delete the selected surface. 4. Click return to exit the .

Step 4: Create surfaces to fill large gaps in the model. 1. Click Geometry > Create > Surfaces > Spline/Filler to create the surface.

2. Clear the Keep tangency check box. The Keep tangency option is valid for surface edge line selection only. It considers curvature of any surfaces attached to the selected edges and tries to create a surface tangent to them. This helps to form a smooth transition to the surrounding surfaces. 3. the entity type is set to lines. 4. the Auto create (free edges only) check box is selected. The Auto create option is valid for free surface edge line selection only. It simplifies the selection of the lines bounding the missing surface. Once a line is selected, HyperMesh automatically selects the remaining free edges that form a closed loop, and then create the filler surface. 5. Zoom into the area indicated in the following image. Pick one of the red lines bounding one of the gaps (missing surfaces). HyperMesh automatically creates a filler surface to close the hole. Repeat this step to create a filler surface in the other gap. HyperWorks 13.0


Chapter 2: Geometry

Area of missing surfaces

6. Click return to exit the .

Step 5: Set the global geometry cleanup tolerance to 0.01. 1. Press O to go to the Options . 2. Go to the geometry sub-. 3. In the cleanup tol = field, type 0.01 to stitch the surfaces with a gap less than 0.01. 4. Click return to exit the .

Step 6: Combine multiple free edge pairs at one time with the equivalence tool. 1. From the menu bar, click Geometry > Edit > Surface Edges > Equivalence 2. Activate the equiv free edges only check box.

3. Select surfs >> all. 4. that the cleanup tol = is set to 0.01, which is the global cleanup tolerance specified in the options . 5. Click the green equivalence button to combine any free edge pairs within the specified cleanup tolerance. Most of the red free edges are combined into green shared edges. The few remaining are caused by gaps larger than the cleanup tolerance. 76 HMD Introduction


Chapter 2: Geometry

Step 7: Combine free edge pairs, one pair at a time, using the toggle. 1. Go to the toggle sub-. 2. In the cleanup tol = field, type 0.1.

3. In the graphics area, click one of the free edges shown in the following image. Use toggle to equivalence the other edges shown in the image

Area where free edges need to be toggled

4. Rotate and zoom into the area if needed. When the edge is selected, it will change from red to green, indicating that the free edge pair has been equivalenced.

Step 8: Combine the remaining free edge pair using replace. 1. Go to the replace sub-. 2. With the selector under moved edge: active, click the leftmost free edge in the graphics area. that the selector under retained edge: is now active. HyperWorks 13.0


Chapter 2: Geometry

4. Select the rightmost red edge. 5. In the cleanup tol = field, enter 0.1. 6. Click replace.

Once the line is selected, HyperMesh posts a message similar to:

7. Click Yes to close the gap.

Edges to retain and move for replacement


Step 9 (Optional): Save your work. With the cleanup operations completed, save the model.

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Chapter 2: Geometry

2 - Simplifying Geometry This section looks at changing the shape of a part in order to simplify the geometry. Certain details of the shape, such as small holes or blends, may simply not be necessary for the analysis being performed. When these details are removed, the analysis can run more efficiently. Additionally, mesh quality is often improved as well. Changing the geometry to match the desired shape can also allow a mesh to be created more quickly. In this section, you will learn: 

Mesh the part, review the mesh quality and determine the features to be simplified



Remove pinholes, surface and edge fillets



Find and delete duplicated surfaces



Identify part symmetry



Remove pinholes



Create surfaces by filling in gaps

Defeaturing There are many features on a part that are not critical to the structure of the part and have little or no effect on the analysis. These features can include: 

Lightening Holes – For part weight reduction



Edge Filets – For reduction of sharp corners allowing safer part handling



Surface Fillets – To meet manufacturing requirements

These features often are process driven and are not function critical. While our goal is to mesh a part that as closely as possible accurately represents the geometry, these features often degrade the quality of the mesh. As such they can be defeatured out of the design allowing for a substantially improved mesh with little impact on the results.

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Chapter 2: Geometry

Simplifying CAD Tools Defeature (Geometry > Defeature)



Pinholes: Searches for holes within a surface. Fills them in and leaves a fixed point at their previous center.

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

Surf Fillets: Searched for surfaces that act as a fillet between other surfaces and tangentially extends them to achieve a sharp corner.



Edge Fillets: Searches for rounded edge corner and squares them off.



Duplicates: Finds and deletes duplicate surfaces.



Symmetry: Identifies part symmetry and deletes or organizes the results.

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Chapter 2: Geometry

Exercise 2b - Simplifying CAD Tools Step 1: Load the model 02b-SIMPLIFYING-CAD.hm

Step 2: View the model in topology display toolbar to evaluate its integrity. 1. Observe where the model has incorrect connectivity and missing or duplicate surfaces.

Step 3: Find and delete all duplicate surfaces. 1. From the Menu Bar, click Geometry > Defeature > Duplicates

2. Click surfs >> displayed. 3. In the cleanup tol = field, type 0.01. 4. Click find.

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The status bar displays the following message, "1 duplicated surface was found."

5. Click delete to remove any duplicate surfaces.

Step 4: Observe the model again to identify any remaining free edges, or missing or duplicate surfaces. 1. Use the topology display and shaded modes to perform this task. All of the edges in the model should be displayed as explained below:   

green shared edges, indicating that all internal surfaces are connected (equivalenced). red free edges, indicating that, around the external profile & holes, all surfaces edges are not connected (equivalenced) at that edge. yellow T-junction edges, indicating that these edges are connected (equivalenced) and associated with 3 or more surfaces.


Step 5: Removing Edge Fillets 2. Enter the Geometry > Defeature > Edge Fillets 3. Pick the displayed surfaces. 4. Enter 1 for the min radius. 5. Enter 20 for the max radius. This will guarantee all edge fillets are selected. 6. Click find. All of the edge fillets will be highlighted.

If there were fillets that you did not wish to be removed they could be right clicked at the F and they would be deselected and not removed. HyperWorks 13.0


Chapter 2: Geometry

7. Click remove. All of the edge fillets will be removed leaving sharp corners in their place. This will result in better mesh quality as will be shown in the next chapter.

Step 6: Removing Surface Fillets 1. Select the surf fillets sub-. 2. Select the displayed surfaces. 3. Set the min radius to 0.1. 4. Set the max radius to 5. 5. Click find.

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The radius around the hole will be selected but the larger fillet will not be. This is because the larger fillet has a radius of 7 and thus was not found. 6. Click the two surfaces that make the larger fillet (Set the max radius to 8) to highlight them.

7. Click remove. The fillets will be removed once again providing for a better mesh quality.

Step 7: Removing Holes 1. Select the pinholes sub . 2. Select the displayed surfaces. 3. Set the diameter< field to 5. HyperWorks 13.0


Chapter 2: Geometry

4. Click find.

The small holes will be selected. Once again if there is a hole that you do not wish to take out simply right click on it to deselect it. 5. Click delete

The holes are removed and a fixed point is placed at their former center. This will guarantee a node is in that location but the points can be removed if no node is needed.

Step 8: Removing Edge Fillets 1.

Select the edge fillets sub-.

2. Select the surface shown in the picture below to remove the round edge.

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3. Set the edge option as round

.

4. Enter 1 for the min radius. 5. Enter 20 for the max radius.This will guarantee the edge fillet is selected.

6. Click find. The edge fillet will be highlighted.

7.

Select this edge fillet and click remove.

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8. Use Geometry > Quick Edit > toggle edge to complete the model.

Step 9 (Optional): Save your work. With the cleanup operations completed, save the model.

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Chapter 2: Geometry

Topology Repair: Strategy 

Understand model size & scale to determine an appropriate global element size



Set a cleanup tolerance based upon the previously determined global element size. o

Set appropriate value in Preferences > Geometry Options > geometry

o

Cleanup tolerance specifies the largest gap size to be closed by topology functions

o

Tolerances > 15-20% of global element size can cause mesh distortions

o

Can change value multiple times for work on various areas of the model



Use topology Visualization Options tools to determine what needs to be repaired.



Use Edge Edit > equivalence to combine as many free edge pairs as possible o



Make sure surfaces are not collapsed in undesirable manner

Use Edge Edit > toggle to combine any remaining free edge pairs, 1 by 1 o

use Edge Edit > replace function if more control is needed



Find Defeature > duplicates to check for any duplicate surfaces and delete them



Use Geometry > Create > Surfaces > Spline/Filler to fill in any missing surfaces.

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Chapter 2: Geometry

3 - Generating a Midsurface This section uses CAD geometry data for a thin solid clip. Because of the small thickness of the part, it is assumed that it will be modeled for FEA as shell elements. The elements will be created on the mid-plane of the part. In this section, you will learn how to: 

Create and Edit a midsurface



Visualize the midsurface by using shading options and transparency

Midsurfacing: Introduction Often the most accurate representation of a part is through the use of shell elements. These elements best represent parts that are relatively thin compared to their overall surface area and typically have a uniform thickness. Shell elements have no physical thickness representation; they are displayed as two dimensional entities whose thickness is simply a numerical value assigned to them. FE Solvers assume the shell element to lie at the middle of the thickness. As that is the case, the mesh created on the surfaces needs to lie at the mid-plane of the part. CAD geometry is usually created as either a solid part or a series of faces representing a solid part. Using the midsurface tool in HyperMesh, proper surfaces can be extracted that lie on the mid-plane of the part and can be meshed appropriately.

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Midsurfacing: Tools Midsurfaces can be created using Geometry > Create > Midsurfaces  auto midsurface – This sub allows you to extract, in one step, the midsurface of a more complicated group of surfaces that represent a solid part.



closed solid - When selecting surfaces, the closed solid mode simplifies the for s who do not intend to use any of the advanced options. While in closed solid mode, select a single surface of the solid geometry and click extract (or middle mouse). The function automatically determines the enclosed volume the selected surface belongs to and extracts the midsurface from it.



incomplete solid - When selecting surfaces, the incomplete solid mode provides for additional options for selecting and orienting the surfaces defining the body to extract. While in closed solid mode, select a single surface of the solid geometry and click extract (or middle mouse). The function automatically determines the enclosed volume the selected surface belongs to and extracts the midsurface from it.

 surface pair – The surface pair sub offers a simplified function that allows you to extract a midsurface from two faces that represent the two sides. This function creates one surface that forms the midsurface.



combine with adjacent plates - This option takes any surfaces that are adjacent to the two surfaces selected, and extends, trims, or projects the midsurface created to match the surrounding midsurfaces.

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Chapter 2: Geometry



combine all adjacent plates - This option takes any surfaces that surround the two surfaces selected, and extends, trims, or projects the midsurface created to form continuous geometry with shared edges.

 quick edit - Use the Quick Edit sub to quickly repair a midsurface by correcting its targets. It should be used after you have created (or attempted to create) a midsurface using the auto midsurface sub . You first select a surface that you want to edit/repair; this surface can either be a midsurface that was created earlier, or a surface that is part of the solid.

You will notice the appearance of new temporary entities displayed in three colors (yellow, cyan and red), which represent the following: 

Surface to offset (yellow): The original surface from which the middle surface was created by an offset with a variable direction and distance.



Targets (red): -controlled handles that allow you to change the direction and distance of the offset. The targets are the red segments that connect points on the initial surface with the points where the surface must be offset. The offset is interpolated in between the assigned targets.

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



Midsurface to Edit (cyan): The midsurface (in-progress) that you can modify by re-asg the targets. This surface is updated as you make changes to the targets. The midsurface (in-progress) can be made permanent by clicking the update button, when you are satisfied with your editing results.

assign target - Use the Assign Target Midsurface sub to repair a midsurface by correcting its targets. It functions similar to the Quick Edit sub , but has more advanced features. As with the Quick Edit sub , it should be used after you created (or attempted to create) a midsurface. You should first select a surface to edit/repair. This surface can either be a midsurface that was created earlier, or a surface that is part of the solid.

You will notice the appearance of new temporary entities displayed in different colors (yellow, cyan and red), which represent the following: 

Surface to offset (yellow):The original surface from which the middle surface was created by an offset with a variable direction and distance.



Midsurface to edit (cyan): The midsurface (in-progress) that you can modify by re-asg the targets. This surface is updated by clicking accept target after you make changes to the targets. The midsurface (in-progress) can be made permanent by clicking the update button, when you are satisfied with your editing results.



Targets (red): -controlled handles that allow you to change the direction and distance of the offset. The targets are the red segments that connect points on the initial surface with the points where the surface must be offset. The offset is interpolated in-between the assigned targets.

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

New targets (green): New targets that have not been accepted, thus they do not affect the midsurface. Click accept target to accept them, turning them to red and incorporating their effects into the cyan midsurface.



Targets being combined (purple): New and existing targets that will be combined once they are accepted.



Target planes: Planes parallel to the offset surface drawn at target point, which can be displayed for reference.



replace edge - Use the Replace Edge sub to close gaps and slivers by replacing one edge with another. This function is the same as the one in the Edge Edit and is available here for convenience. The geometry shape doesn’t change, just the topology.



extend surface - This sub extends or retracts the edges of selected surfaces to meet other selected surfaces, or to close gaps between surfaces or holes within a selected surface. Several options affect how surfaces extension behaves, including enabling or disabling the ability to shorten edges as well as extend them, or to force the extended edges to attempt to maintain the overall shape of the surface.

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

View / assign thickness - Use the View/Assign Thickness sub to review the thickness of surfaces (including midsurfaces), or change them. Surfaces that have thickness data stored are drawn with lines (probes) extending from each vertex of the surface.

The length of these probes represents the thickness at those locations. Only surfaces created in the Midsurface have thickness information defined by default, but you can use this sub to define/set a fixed, uniform thickness for any surface. The assign thickness option allows you to set a constant thickness value to selected surfaces. To perform this task: enter the new thickness value, select the surfs that you wish the value to be applied to, and click the assign button which appears when you activate any of the controls in the assign thickness portion of the sub . To undo, click reject before leaving the sub .

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Midsurfacing: Process & Strategy 1. Obtain a closed volume of surfaces or solids 

Midsurface : auto midsurface requires an enclosed volume



Use topology repair techniques if needed

2. For complex parts, try defeaturing the surface defining the volume 

This simplifies the part and may give better results with create : solid

3. Generate the midsurface using Midsurface > auto midsurface 

Use surface pair for areas that need more control



Use midsurface : editing tools for midsurfaces that need fine tuning

4. View the midsurface and correct errors using the midsurface editing functionalities 

Can generally use quick edit

Midsurfacing: Tips 1. Don’t be afraid to delete surfaces 

It is sometimes easier to just recreate the midsurface manually.

2. Use your 3D geometry as a reference to make new surfaces. 3. Save copies of surfaces you like in a separate comp in case you do something you don’t like. 4. Be sure to toggle on the view of your surface points. 

Release points



Replace points

5. When using the plate edit option, don’t defeature fillets. 6. Use Surface edit > Self Intersecting Surface to control the trimming of intersecting surfaces, instead of having the auto-midsurface tool do it for you. 7. Defeature fillets on a surface, not a solid.

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Chapter 2: Geometry

Exercise 2c - Midsurface This exercise will cover the basic aspects of geometry repair and preparation for meshing. It will cover repairing problems with the geometry, midsurfacing and defeaturing.

Step 1: Open the file 02c-MIDSURFACE.hm

Step 2: Review the model 1. Zoom, Rotate and Pan the model to find the issues with it.

[HINT 1]: Use the Visualization Options Icon to find edges to fix.

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[HINT 2] You can use Geometry > Quick Edit and play with Tolerance value to fix issues. The tolerance is used to determine if two surface edges are the same and if two surface vertices are the same. The default tolerance controls if two surface edges are close enough to be automatically combined to shared edges (green edges). If you want you can specify a different value, greater than the default value. Increasing the tolerance can cause serious problems. When this value is set, any features equal to or less than the tolerance are eliminated. If there are edges present that are important to the surface, that surface will be distorted, or will fail to trim properly. The tolerance value should not be set to a value greater than the node tolerance set in the options (Preferences > Geometry Options) to be used for your element mesh. 2. Use geometry repair tools to fix the following issues: o

Duplicate Surfaces to delete with Geometry > Defeature > duplicates

o

Missing Surfaces to create with Geometry > Quick Edit > filler surface

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o

Free Edges to equivalence with Geometry > Quick Edit > toggle edge

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Step 3: Create and Edit the Midsurface 1. From the menu bar select Geometry > Create > Midsurfaces > Auto. This brings you to the auto midsurface sub- in the midsurface .

2. Set the switch to surfs. 3. Toggle to closed solid. 4. With the surfs button selected pick one displayed surface, the “closed solid” option will select all surfaces attached. 5. Click on “extract options …”, you will be placed in a secondary , and set offset from the first toggle menu. Click Return to be back in the midsurface main .

6. Click extract. A new component will be created called Middle Surfaces and the new mid plane surfaces will be placed in it. Additionally the original component will be set to be partially transparent so the Middle Surfaces can be seen.

7. Turn off the display of the original component so that only the Middle Surfaces are displayed.

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8. There are multiple issues with the model. They need to be repaired. Rotate the model as shown below and zoom into the area.

9. Zooming in reveals some serious problems with the midsurface in this area. These can be fixed with the Geometry > Create > Midsurfaces > quick edit sub-.



Chapter 2: Geometry

10. If you have exited the Midsurface enter it again. 11. Select the quick edit sub- 12. Set the target type to point to point. 13. Set the target location to as selected. 14. Leave the remaining settings and pick the surface shown by the blue arrow (picture above).

The display will now show the way in which HyperMesh decided to create the middle surface. That needs to be corrected.

15. Pick the point in the green circle (circle labeled 1) to indicate the point “point to offset” whose offset you wish to fix (see image below). 16. Pick the point in the blue circle (circle labeled 2) to indicate which point “pilot point” it should have been offset to (see image below). You will need to hold down the left mouse button to highlight the line, and then click on the line to select a node.

17. HyperMesh then shows what the new surface offset will look like. This is now correct.

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18. Select update. 19. Rotate the model slightly; a green line is left where the problem area was previously. Use the toggle sub in the Geometry > Quick Edit > toggle edge sub to toggle the edge from a shared edge to a suppressed edge.

20. Fit the model to the screen, zoom in and rotate on the highlighted area below.



Chapter 2: Geometry

21. Go to the Geometry > Create > Midsurfaces and select quick edit sub-. 22. Set the target type to point to point. 23. Set the target location to as selected. 24. Leave the remaining settings and pick the surface shown by the blue arrow (picture above).

The display will now show the way in which HyperMesh decided to create the middle surface. That needs to be corrected.

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25. Pick the point in the green circle (circle labeled 1) to indicate the point whose offset you wish to fix (see image below). 26. Pick the point in the blue circle (circle labeled 2) to indicate which point it should have been offset to (see image below). You will need to hold down the left mouse button to highlight the line, and then click on the line to select a node. 27. HyperMesh then shows what the new surface offset will look like. This is now correct. Select update.

28. Repeat step 24-25-26-27 using Point 3 and 4. [HINT] Use Visualization Mode: Wireframe Geometry while you’re working with point 3, 4.

29. HyperMesh then shows what the new surface offset will look like. This is now correct. Select update.



Chapter 2: Geometry

30. Rotate the model slightly; a green line is left where the problem area was previously (see pictures below). Use Geometry > Quick Edit > toggle edge sub to toggle the 2 green edges.

31. Rotate the model slightly; a red line is left where the problem area was previously (see pictures below).

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Chapter 2: Geometry

32. Go to the Geometry > Create > Midsurfaces > extend surface sub-.

33. Use setting as you can see in the picture above and pick the surfaces shown by the arrow (picture below).



Chapter 2: Geometry

34. (Optional) Chech the model and see if there are still remaining issues. Use the midsurfacing tools, point replace, filler surface and other geometry tools to repair the part, if needed.

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Chapter 2: Geometry

Midsurfacing: Extraction Options…

The following options are available by clicking on the extraction options... button:

 

offset – Choose offset to create pieces of the middle surface by offsetting the model's side surfaces towards the middle. This is the traditional approach for midsurfacing in HyperMesh. Surface pairing is automatic and pairs can be further organized using the Plate Edit .  align steps/ keep jump steps – This is available only when you select offset. In the case of a part that has different "steps" of thickness, such as a flat sheet that is twice as thick at one end as the other but uses an abrupt step-like change in thickness instead of a constant slope or curve. The align steps option will align midsurfaces whereas keep jump step will produce steps between the various midsurfaces as in the original model.



Chapter 2: Geometry

 auto mid position / mid position – This is available only when you select offset and align steps. If you select auto mid position, HyperMesh will create a midsurface parallel to the largest side of the volume. This midsurface includes "offset" data to represent the changes in distance between the midsurface and the smaller faces at each "step". If you select mid position, you have to define the offset of the midsurface, using a value from 0 to 1, to specify the offset from the largest side of the volume.

The midsurface (with orange nodes) is parallel to the larger face of the solid plate





offset+planes – Choose offset+planes to use a midsurfacing algorithm to identify the places in the model where a piece of plane can be used as a middle surface. The remaining places in the model that were not identified are used to construct the middle surface via the offset of the model's sides.



offset+planes+sweeps – Choose offset+planes+sweeps to use a midsurfacing algorithm to identify the places where a piece of plane or a piece of a sweep surface can be used as a middle surface. A middle surface is constructed again using the remaining places in the model that were not identified via the offset of the model's sides.

allow rerun – Adds the rerun option to the Auto Midsurface . The rerun option allows you to visualize which points the extraction tool believes to be linked (and which will therefore collapse to the same point on the midsurface), and manually define lines / line chains to establish the linkage between points that should collapse to the same location. 

Starting Solid entity

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



Auto-extract its midsurface; Its result contains gaps



Rejecting the midsurface, prepare for rerun, and then extracting again displays the same midsurface, along with blue highlighting of the lines that connect associated points.



Problem caused by the failure of extraction; it could be fixed by manually specifying the fillet curves as additional lines to collapse.

use base surfaces – The use base surfaces option allows you to select the separatebut-aligned faces that you wish to treat as if they were continuous (in the image below, these would be the three bottom faces) and create the multiple midsurfaces based on them. 

Extract midsurfaces from multiple solids as if they were a single solid using the align steps option.



Chapter 2: Geometry





It uses a new base surfaces setup... Button that allows you to select the desired based surfs to add; new midsurfaces are created at the specified distance from the selected base surfaces.



Use this feature to create aligned midsurfaces for non-aligned solids, by specifying each solid and its offset separately, using a different offset for each.

thickness bound / no thickness bounds – This option allows you to set the minimum and maximum thickness of the plates in the part. If thickness bounds are specified, middle surfaces are only created for plates with a thickness that falls into the specified range. This option can improve the robustness of the results and speed up middle surface creation. If you choose no thickness bounds, midsurface extraction still uses the max thickness ratio. This is the highest acceptable ratio of the thickest plate’s thickness to that of the thinnest plate. max thicknesses ratio - This is the highest acceptable ratio of the thickest plate’s thickness that of the thinnest plate.

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

max R / T ratio – This parameter, while always present in the midsurface function, has now been “exposed.” Previously this value was hard-coded into the function at a value of 2.0. thickness based stitch tol - When the thickness based stitch tol checkbox is active, the final stitching of midsurfaces is performed with a locally-defined tolerance of 1/5 of the local thickness. If unchecked, global cleanup tol from the Options is used for stitching.

o

R/T Information and Tips  The R/T ratio is taken into on T-, X- and more complex connections only, as in the center of the picture below. On a curve without a T-connection (like on the right side on the picture) it does not apply.  If R/T is greater than the value specified in the , then this location will not be recognized as a junction.  If T is different on different sides on the junction (as in the above picture), then the maximum T is used.  Will work with fillets that have a variable radius across their length.  Use of this parameter with a high value can result in situations where it is not valid to use a midsurface representation. If these are not areas of high stress and the results in this area are not of interest, then it is acceptable. This option does not affect the core midsurface algorithm.



extract by component / cross components – This option is useful when you are trying to extract the midsurface of multiple parts in a single step. If it is toggled to extract by component, it assumes that each part is contained in its own component, so it extracts the midsurface of one component at a time. If your model contains a single part organized in multiple components, you should toggle this option to cross components.



result in Middle Surface comp/result in current comp – This toggle specifies if the midsurfaces are created in the Middle Surface component (created if it does not exist) or in the current component. It is recommended to use the result in Middle Surface comp setting.



Chapter 2: Geometry



sort Middle Surface comp into – This option specifies how to organize the midsurfaces generated in the Middle Surface component when the sort button is clicked. The original comp option organizes the midsurfaces into their parent surface/solid components.

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Chapter 2: Geometry

Midsurfacing: Plate Edit… Use the Plate Edit to manually edit a plate when the automatic detection of plates is not correct.

Plates are a group of surfaces in the model in which the middle surface will be inserted. Each plate has two sides: blue and green. HyperMesh inserts the middle surface between the two sides of each plate. To open the Plate Edit , click plate edit in the auto midsurface sub. The following options are available by clicking on the plate edit... button:

Controls are grouped into three main columns, with command buttons along the rightmost edge: 

First column, selection of Plate type.



Second column is used for editing plate with visualization option to turn on/off plates and non plates.



Last column is used for selecting entire plate from graphic area. Multiple plates can be combined into single plate using merge plate option.

When you enter the Plate Edit , HyperMesh organizes the surfaces into components that reflect their plate type. To display the plates as per their component color, change the geometry display mode to

on the Visualization toolbar.



Chapter 2: Geometry

Plate types: •

Planar plate - Group of surfaces that will have a planar surface inserted in between them. The inserted middle surface is a trimmed piece of planar surface. Planar plate's midsurfaces are trimmed using plate edges.

•

Sweep plate - Group of surfaces that will have a sweep surface inserted between them.

•

Offset plate - Group of surfaces that will have a non-planar surface inserted between them. Midsurface will be created from offsetting one of the side plates (green plate).

•

Auto plates - Group of surfaces that automatically have a midsurface inserted between them. An algorithm determines the plate type for the group of surfaces that has a midsurface inserted between them.

•

Transition surface - Transition surface provides more information to the algorithm regarding inserting surface where two regular plates are intersecting. An algorithm calculates how far intersecting plates can be extended based on the transition surface.

•

Switch side - Each plate has two sides (blue and green) between which midsurface is inserted. By default, HyperMesh generates the midsurface by offsetting the green side of the plate. If you are unsatisfied with the midsurface that was generated from the green side and want the midsurface to be offset from the blue side, click switch sides. HyperMesh offsets the midsurface from the new green side, which was blue before using switch side.

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•

Not a trim surface - Moves the selected surface that you do not want to be used in the midsurface extraction process into the component, ^Not a trim surface. HyperMesh ignores the surfaces in the ^Not a trim surface component during the extraction process.

•

Plate edge - Acts as cutting plane for planar plates. HyperMesh trims the inserted midsurface in the planar plate at the plate edge.

•

Merge plates - Combines multiple plates into a single plate.

Plate Display options: 

plates on/off - Turns the display of plates on and off.



non-plates on/off - Turns the display of non-plates (transition and not trim surface) on and off.



show related midsurface - Select this check box to only display the midsurface associated with a plate in the graphics area.



restore displayed comps - Select this check box to restore the display of the components, as they were before you entered the Plate Edit , after you exit the .



clear all - Deletes all of the plate information.

How to isolate the required plate you wish to edit. 1. Activate full plate selector > surfs 2. From the graphics area, select the plate you want to isolate. 3. Activate single surface selector > surfs

How to change the plate type. You can change a group of surface's plate type in the Plate Edit . For example, if a group of surfaces are assigned the plate type Planar, but the offset plate will provide better results, you can change its plate type to offset. 1. From the plate type drop-down menu, select a new plate type based on the geometry. Activate the full plate selector 2. Activate the full plate selector > surfs. 3. From the graphics area, select the plate(s) that you would like to change the plate type for. 4. Click merge plates. HyperMesh changes the plate type. 5. In the dialog that says, "Plate type was changed", click OK. 118 HMD Introduction


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How to move fillets/surfaces to a transition surface or not a trim surface. If some fillets/surfaces are in an incorrect group of plates, you can use the single surface selector to move them to a transition surface by clicking transition surface, or you can elect to not use them in the midsurface extraction process by clicking not a trim surface. 1. Activate single surface selector > surfs. 2. From the graphics area, select the fillets/surfaces you wish to move. 3. Click transition surface. Or Click not a trim surface. HyperMesh creates a new component, ^Not a trim surface. 4. You can perform similar actions on other type of plates.

How to generate a new updated midsurface. If some fillets/surfaces are in an incorrect group of plates, you can use the single surface selector to move them to a transition surface by clicking transition surface, or you can elect to not use them in the midsurface extraction process by clicking not a trim surface. 1. When you are finished editing the plates, click update. HyperMesh removes the old midsurface and regenerates a new, updated midsurface based on the plate information that you modified. 2. When your model is organized correctly and you are ready to go back to the auto midsurface , click return.

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Exercise 2d - Midsurfacing with Advanced extraction options This exercise includes CAD geometry data for a box with thin ribs inside of it. Because the geometry consists of thin planar sections, it is assumed that it will be modeled for FEA as shell elements. The elements will be created on the mid-planes of each section In this exercise, you will learn how to: 

Use the offset+planes+sweeps option when midsurfacing.



Manually correct gaps in an auto-generated midsurface using the plates edit function.

Step 1: Retrieve and View the Model File 1.

From the menu bar, click File > Open.

2.

In the Open Model dialog, open the 02d-PLATE-EDIT.hm model file.

3.

From the menu bar, click Geometry > Create > Midsurfaces > Auto.

4.

In the auto midsurface , click the first toggle and select closed solid.

5.

In the graphics area, click any surface.

6.

Click extraction options.

7.

Select offset+planes+sweeps option from dropdown menu.

8.

Click

.

9.

Click

.

10. On the Visualization toolbar, change the visualization to Shaded Geometry and Surface Edges (

).



Chapter 2: Geometry

11. To review the generated misdurface, hide the Body.1 component in the Model browser. Some of the plates do not properly cross.

Step 2: Use Plates Edit to Resolve Midsurface Gaps 1.

In Model browser display the Body.1 component.

2.

On the Visualization toolbar, set the geometry display mode to Mixed (

3.

In the auto midsurface , click plates edit. HyperMesh populates the Model browser with plates that were detected by the tool. Note:

4.

)

If you haven’t yet extracted middle surface using either offset+planes or offset+planes+sweeps option then model doesn’t have information about plates yet. So the plate components will not be populated in this situation.

In the Model browser, hide the Body.1 and Middle Surface components.

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5.

Activate the full plate selector, and select the green face in the graphics area. HyperMesh selects all of the plates in the ^Planar plate #0 component.

6.

To hide all of the plates in the ^Planar plate #0 component, right-click on the green face in the graphics area.

7.

Repeat steps 2.5 and 2.6 for the three remaining exterior sides. The components ^Planar plate #2, ^Planar plate #3, and ^Planar plate #4 are hidden.

8.

Select any face from the long interior rib, as illustrated in the image below. This rib was split into three groups by the algorithm, and need to be reunited into one plate component.

9.

Select the two remaining plates from the long interior rib.

10. To merge these three plates into single planar plate specify plate type as planar.



Chapter 2: Geometry

11. click or middle-click in the graphics area. The three plates are now the same color, in a single component. 11. To merge the two remaining internal ribs, repeat steps 2.8 through 2.11.

12. Click update. 12. Click

.

13. To review the generated misdurface, hide the Body.1 component in the Model browser. The plates are closer together, but they are still not the full length of the rib due to the holes that trim the plates.

Step 3: Use Plates Edit a Second Time to Resolve Remaining Gaps We will need to tell the auto-midsurface algorithm not to trim the plates where the holes are. 1.

In the auto midsurface , click plates edit. HyperMesh populates less plate components in the Model browser because some plates were merged in the previous steps.

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2.

Hide all of the components except ^Plate edge.

3.

Using the single surface selector, select all four internal surfaces of the holes in the graphics area.

4.

Click . HyperMesh organizes the selected surfaces into a new component labeled ^Not a trim surface.



Chapter 2: Geometry

5.

Click update.

6.

Click

8.

To review the generated midsurface, hide the Body.1 component in the Model browser. There is now a yellow edge where the plates meet, which indicates that the plates are intersected correctly. It would have been possible to reorganize the plates and create the not a trim surface component at the same time.

.

Step 4 (Optional): Save Your Work 1.

From the menu bar, click File > Save.

Summary The model now contains surfaces on the mid-plane of the part. You used offset+planes+sweeps and plates edit to avoid gaps in the generated midsurfaces. You can now mesh these surfaces, or further modify their topology, depending on the requirements of the analysis.

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Midsurfacing: Midsurface Mesh Tool The Midsurface Mesh Tool is located at Mesh > Create > MidSurf Mesh menu. This tool allows you to create a midsurface, create finite elements and assign them related thickness.



Chapter 2: Geometry

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Midsurfacing: Map Mid-Mesh Thickness Tool The Map Mid-Mesh Thickness Tool is located at Mesh > Edit > Elements > Midmesh Thickness menu in RADIOSS, OptiStruct, Abaqus, LS-DYNA, and Nastran profiles. This tool can be used for calculating the thickness of a mid-mesh from the solid geometry. The thickness will be assigned on the mid-mesh either on node card, element card, nodal thickness on element card or also as properties on elements depending on the solver profile. This tool allows you to create a midsurface, create finite elements and assign them related thickness.



Chapter 2: Geometry



Input Section – The mid-mesh and solid can be specified by selecting entities in the HyperMesh session interactively, or optionally, external geometry or FE solver decks can also be selected as input

FE and Geometry displayed Traditional Element Visualization



Thickness Output Options (solver dependent)  Clicking the Calculate Thickness button will begin the operation. The thickness will be computed and assigned on the mid-mesh. o

Nodal thickness on elements

o

Properties on elements

o

Minimun thickness

o

Maximun thickness

o

Assign offset to elements

o

Maximum Thickness Range Interval:

o

Correction method:

o

Scaling at corners (0,10):

o

Max Midmesh / Solid angle (0,90):

o

Max thickness gradient (0,10):

o

Save log file:

o

…

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Chapter 2: Geometry



View Options – In the View section, there are several options for visualization:



Element Coloring by thickness: Thickness Contour Applied 3D Element Visualization



3D Element Representation: 3D Element Visualization



Highlight Corrected Elements: 3D Element Visualization Corrected Elements Highlighted



Chapter 2: Geometry

4 - Generating and Editing Surfaces In this section, you will learn how to: 

Create surfaces



Edit surfaces

Generating Surfaces The Surfaces is located at Geometry > Create > Surfaces and it allows you to create surfaces using a wide variety of methods:



Square (



cylinder full / partial ( surface primitives



cone full / partial ( primitives



sphere four nodes / partial ( primitives



torus center and radius / three nodes / partial ( dimensional torus surface primitives



Spin (



drag along vector / line / normal ( lines/nodes along a vector/line/normal



ruled (



spline/ filler ( existing surface



skin (

) -- Creates surfaces by skinning lines



fillet (

) -- Creates constant radius fillet surfaces across surface edges

) – Creates two-dimensional square surface primitives ) – Creates three-dimensional full/partial cylinder

) – Creates three-dimensional full/partial cone surface

) – Creates three-dimensional sphere surface

) -- Creates three-

) -- Creates surfaces by spinning lines or a node list around an axis ) -- Creates surfaces by dragging

) -- Creates surfaces by interpolating linearly between lines or nodes ) --, Creates surfaces by filling in gaps, such as a hole in an

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Chapter 2: Geometry



from FE (



meshlines ( ) -- creates lines from nodes or plot elems; mesh lines closed chains of mesh lines can be used to generate surfaces or apply loads.

) -- Creates surfaces that closely fit a selection of shell elements

Editing Surfaces The Surfaces Edit is located at Geometry > Edit > Surfaces and it allows you to perform a variety of surface editing, trimming, and creation functions. This also allows you to offset surfaces in their normal direction.



trim with nodes – Allows you to trim (split) a surface using nodes. The surface can be trimmed with two nodes, with multiple nodes, or with a node normal to and edge.



trim with lines – Allows you to trim/split surfaces using a line (or a group of lines). There are three methods (Trim with cut line, Trim lines, With offset line)



trim with planes / surfs -- Allows you to trim or split surfaces with another surface or a plane. This function determines the intersection of the selected surfaces and a plane or a surface and then trims the original surfaces at this intersection



untrim -- Allows you to remove trim lines so that the trimmed surfaces return to their previous, untrimmed state



offset -- Allows you to offset a group of surfaces by a given distance along the normals of those surfaces



extend -- Allows you to extend or retracs the edges of selected surfaces to meet other selected surfaces, or to close gaps between surfaces or holes within a selected surface. Several options affect how surfaces extension behaves, including enabling or disabling the ability to shorten edges as well as extend them, or to force the extended edges to attempt to maintain the overall shape of the surface.



Chapter 2: Geometry

Input

Action

max extension / extend over edges

Max extension: extend the surface using a maximum extension distance.

to surfaces

This choice is available when Extend over edges is selected. The extending surfaces will extend as far as necessary to meet these ones.

by distance / by thickness multiplier

For by distance, type in the maximum distance that you wish the surfaces to extend.

Extend over edges: extend a surface over edges to another surface

For by thickness multiplier, type in the multiple of the surfaces' assigned thickness that yields the maximum distance you wish the surfaces to extend. by filling gaps / by by distance: This is the literal distance that selected edges will extend, distance / to surfaces measured in the same units that the model was created for. by filling gaps: extends the edges of the hole to fill the gap. surfs: to extend selector

Use this selector to pick only the surfaces that you wish to extend. If you selected any shared (green) or non-manifold (yellow) edges as lines: to extend over, then this selector allows you to specify the corresponding surfaces so that HyperWorks knows which surface to use to determine the plane of extension for the shared/non-manifold edge. Additionally, you may need to use use this selector to specify any "target" surfaces, particularly if you use the cross extension option described below. Edges will only extend toward surfaces that are also selected, even if those additional surfaces have no extending edges. These recipient/target surfaces will also be trimmed, if the trim result surfaces checkbox described below is active.

cross extension / surfs: to target selector

cross extension allows for all input surfaces to be used as both extension and target surfaces. This is useful for doing bulk extensions where all selected surfaces should extend to others within the selection. The input surfaces will not extend beyond the specified max extension distance, nor will any of their edges extend if there are no other surfaces within the max distance. When selecting this option for extending a surface over an edge, then all selected surface/edge combinations will be extended or shrunk. Despite the name, in this case the surfaces will not cross through each other; having selected to surfaces ensures that they will meet rather than intersect. surfs: to target simply extends the surfaces toward other surfaces. You must use this selector to pick the destination surfaces; the extended surfaces will then extend up to the specified distance to meet those surfaces. If the target surfaces are too far away, no extension occurs. When using the surfs: to target option, you can select surfaces already selected as surfs: to extend. Selecting the same surfaces in both surfs: to extend and surfs: to target produces the same result as the cross extension option. When selecting this option for extending a surface over an edge, then the

HyperWorks 13.0


Chapter 2: Geometry surfs: to extend that you have selected edges for in lines: to extend over will extend toward the surfaces that you select with the surfs: to target selector. The target surface does not need to be selected as an extending surface. lines: to extend over

Pick the edges that you wish to extend. The surfaces will be extended across these lines. If you select a free edge, this also selects and highlights the corresponding surface.

surfs: to extend

Pick the surfaces that you wish to extend.

surfs: to target / cross Extended surfaces will extend in the direction of surfaces selected in surfs: extension to target. If cross extension is selected, all the selected line and surfaces will be extended. trim result surfaces

If the checkbox is on and all selected surfaces extend or shorten to have their edges meet, then the selected surfaces will be trimmed or stitched regardless of which components they belong to. If the checkbox is off, the result varies further: If the selected surfaces are in the same component, they will not be trimmed but they will be stitched. This is the default stitching behavior for • surfaces in the same component. If the selected surfs are in different components, they will not be trimmed or stitched. This is the default stitching behavior for surfaces in different components. If you need them to be stitched, you must do so by way of • edge equivalence (or some other edge editing). If the checkbox is on and the selected surfaces extend through their target surfaces, or even merely to the interior without actually touching any of the target surface edges, the surfaces will be both trimmed and stitched at the intersection regardless of whether or not they belong to the same component. However, if the checkbox is off, the surfaces are not trimmed or stitched, since they do not meet at any edges.



shrink -- Allows you to shrink the surface by drawing all of its edges (including internal edges from holes, etc.) "back" away from their starting location



Chapter 2: Geometry

Geometry Dimensioning Use the dimensioning to change one or more dimensions of existing geometry, thus changing the basic shape of solids and other enclosed volumes. The Dimensioning function can be accessed through Geometry > Edit > Surfaces > Dimensioning.

The dimensioning tool allows you to select dimensions of or between surfaces, and modify those dimensions as required. This is accomplished by means of the use of dimension manipulators. The Dimensioning 's behavior is controlled by several options. In addition, you may wish to read about some advanced considerations in order to better understand some of the behavior that results from changing some of the dimensions of existing geometry. The example below illustrates the sort of reshaping that can be done to a solid entity by altering selected dimensions. NOTE: The beige arrows and their attendant numeric values; these are the dimension manipulators which are used to change the dimensions that they refer to in order to achieve the results shown in the second figure.

Initial dimensions

Modified dimensions

Dimensioning is based on continuous surface offset functionality. It provides assistance in the selection of the surfaces to offset so that a change to the selected dimension can occur, and calculates the offset values required for each surface to achieve the specified dimension.

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Chapter 2: Geometry

Dimension Manipulators A manipulator allows review and modification of a distance between two points. To add a manipulator, select any two vertices using the point 1 and point 2 collectors. A dimension manipulator will appear. A manipulator consists of several objects: 

Dimension line - A segment parallel to the line that connects the selected points, but is shifted off the selected points for visibility. The manipulator direction and manipulator ends are also used, which are the same as the dimension line direction and the dimension line ends.



Pullout lines - Two parallel segments that connect the ends of the dimension line with the selected points.



Lock icons - Arrow (movable) and block (locked) images that indicate the lock state of a manipulator end.



Lock controls - Sphere handles, located near the lock icons, that allow for modifying the lock state of a manipulator end.



Display/input field – A field that displays the current dimension value. This also has an edit mode for specifying a new value or deleting a manipulator.

Dimension manipulator objects.

For a distance to be modified, one or both manipulator ends must move. If at least one end shows a movable lock (arrow), launch the manipulator edit mode by clicking the text. The text is highlighted when the mouse is over the correct location to indicate that a mouse click will launch the input mode. Enter the new distance value and close the input field to accept the value, either by pressing enter on the keyboard or by clicking outside in the graphics area. The new dimension, when possible, will be applied. 136 HMD Introduction


Chapter 2: Geometry

Input field edit mode.

When changing several dimensions, each dimension change is performed separately using the respective manipulator. To delete a single dimension manipulator, open its input field, delete its content and close it. To delete all manipulators, click the clear all button on the . Any manipulators that exist when exiting the will be restored again on the re-entering the . Manipulators are also saved in the database file.

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Chapter 2: Geometry



Chapter 3: 2D Meshing

Chapter 3

2D Meshing 1 - AutoMeshing The optimal starting point for creating a shell mesh for a part is to have surface geometry defining the part. The most efficient method for creating a mesh representing the part includes using the Automesh and creating a mesh directly on the part’s surfaces. The Automesh is a key meshing tool in HyperMesh. Its meshing module allows you to specify and control element size, density, type, and node spacing, and also perform quality checks before accepting the final mesh. A part can be meshed all at once or in portions. To mesh a part all at once, it may be advantageous to first perform geometry cleanup of the surfaces, which can be done in HyperMesh. The purpose for this section is to help you become proficient with using the Automesh ’s meshing module. In this section, you will learn how to: 

Mesh all the surfaces at once specifying different element sizes and element types.



Practice changing the element density along surface edges.



Practice checking element quality and changing the mesh pattern by changing the mesh algorithm.



Preview the mesh on all the unmeshed surfaces.



Practice changing the element type and node spacing (biasing) along surface edges.



Re-mesh surfaces.

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Automeshing The automesh function in HyperMesh allows for the rapid generation of a quality mesh on one or multiple surfaces. Within the automesh there are many options available which provide the a high level of control over the ultimate mesh.

Topology Review Automeshing of surfaces is dependent on surface topology, which is the connection of adjacent surfaces edges. Properly connected edges ensure a properly connected mesh. As discussed in the previous chapter, topology is represented graphically though edge color.




Automeshing: How topology affects the mesh To properly represent a part with shell elements, those elements must be properly connected. Unconnected elements are in effect a slice in a part and all stresses, strains and deformations will stop at the unconnected region. HyperMesh keeps edges in a part. This means that if you see a surface edge in the mesh (unless it is suppressed) you will see that same edge in the mesh. HyperMesh will place nodes along that edge and if the edge is properly connected then there will only be one set of nodes that will be shared by elements on either side of the edge. Node sharing between multiple elements is how elements are connected to each other. Below are examples of how edge topology affects the resultant mesh. There is an example for each of the 4 topological states (colors).

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The Automesh Automesh  Mesh > Create > 2D AutoMesh (F12)




Size and bias Sub

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Mesh with no flow control



Chapter 3: 2D Meshing Mesh with Align Control

Mesh with Align and Size Control

AutoMesh > Interactive > secondary This sub is the most widely used and is the default for automeshing. Within this the sets the desired element size and type, chooses options for flowing and mapping and then is provided with a preview mesh. From within the meshing module there are many options for mesh refinement.

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Chapter 3: 2D Meshing 

Density o

Adjust – Left clicking on an edge will raise the element density on that edge by one, right clicking will lower the density by one. Clicking will provide a new preview mesh with the changes.



o

Calculate – Here the can enter a new element size and either click on an edge to recalculate the density on that edge or click recalc all and change the element size for all the surfaces currently being meshed.

o

Set – This option allows for the setting of element densities on a single or all edges to a set number.

Mesh Style o

From this sub the can indicated the type of mesh to create.

o

This also allows the to define the method or style of meshing. The “style” is the manner in which the mesh transitions between different density values.



Chapter 3: 2D Meshing 

Biasing o



Checks o



The biasing sub allows the to control the distribution of nodes during the nodes seeding by selecting biasing in the form of linear, exponential or bell curve distributions.

The checks sub evaluates the quality of the generated mesh.

General Controls

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Exercise 3a - 2D Shell Meshing and Topology Refinement Step 1: Load the model 03a-2D-MESH.hm. Step 2: Automatic 2D Meshing 1. Go to Mesh > Create > 2D AutoMesh to open the Automesh .

2. Mesh the part with an element size of 5. Set all of the options to match the picture above. 3. Review the mesh. Overall the mesh looks pretty good but closer examination of areas around the part reveals there are some extremely poor quality elements.



Chapter 3: 2D Meshing 4. Manipulate the part using the Pan, Rotate and Zoom functions and identify areas of poor mesh formation. As discussed in the lecture, HyperMesh always maintains all edges in the model except those that are suppressed. Turning the mesh visualization off shows the surface edge lines and reveals that there are many features within the model that interfere with mesh quality. This is very often the case in geometric models imported from CAD. Topology refinement is used to fix those areas to improve the quality of the generated mesh.

Step 3: Topology Refinement The goal of topology refinement is to manipulate the geometry to remove or alter geometric features that cause poor element quality. HyperMesh has many tools, both automatic and manual, to assist in this process. 1. Enter the Geometry > Autocleanup . 2. From the Autocleanup select the edit parameters button.

3. Enter 5 for the element size. 4. Leave the Geometry cleanup option checked and deselect all other options. 5. Click OK. HyperWorks 13.0


Chapter 3: 2D Meshing 6. Select the edit criteria button, Advanced Criteria Table option checked. 7. Enter 5 for the target element size, 3 for the minimum element size and 6 for the maximum element size. 8. Click OK. 9. Select all the surfaces and click autocleanup. HyperMesh has suppressed edges that it felt would not allow elements that met the criteria to be created.

10. Review the part again having a look at the new mesh that was remeshed automatically during the topology modification due to the Meshing Options already defined (Preferences > meshing Options > topology revision: > remesh). You will see that the quality of the mesh has improved drastically.



Chapter 3: 2D Meshing There are still some issues with the mesh though. 11. Using the Mesh > Quick edit improve the quality of the mesh using the following functions: o

toggle edge

o

adjust/set density

o

add/remove point

o

split surf-node; split surf-line;

Step 4: Interactive 2D Meshing While automatic meshing is quick and the overall mesh quality is good, HyperMesh allows the to interactively manipulate a preview mesh, controlling various settings before the mesh is finalized. 1. Delete created displayed elements and enter the Mesh > Create > 2D AutoMesh .

2. Change the toggle from automatic to interactive. 3. Select the surfaces in the Standard collector. 4. Click on mesh to create 2D shell elements. HyperMesh now enters in a secondary .

The green mesh that is shown is only a preview mesh and to see how changes affect it click the green mesh button. The mesh will not be finalized until the return button is clicked.

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5. From this screen try the following functions and see the effect they have on the mesh. o

Adjust the edge densities.

o

Recalculate the entire model to have a 6mm element size.

o

Change the mesh style so that the element type is all trias and then all R-Trias.

o

Alter the biasing on edges and determine the difference between linear, exponential and bell curve biasing.

o

Recalculate the mesh to have 5mm quad elements on all surfaces.

After each interactive change, click on mesh to update your green mesh to see effects. 6. Click on return to save the mesh.

Step 5: Model Organization As this exercise will demonstrate the differences between meshing options, multiple components will be necessary to separate the various meshes. 1. Create two new components called AlignOnly and AlignAndSize and make them distinct colors. 2. Organize a copy of all the surfaces into both collectors.




Step 6: Meshing Options There are a few options in the 2D AutoMesh which can have a profound effect on the mesh created. This section will explore these options. 1. Make the AlignOnly collector current and the only collector visible. 2. From the 2D AutoMesh , size and bias sub , next to flow select the align option. Leave the twe size boxes un-selected.

3. Select the surfaces in the AlignOnly collector and click on mesh.

4. Make the AlignAndSize collector current and the only collector visible.

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Chapter 3: 2D Meshing 5. From the 2D AutoMesh , size and bias sub , next to flow select the align and size options.

6. Select the surfaces in the AlignAndSize collector and click on mesh.

7. Utilizing the isolate function in the Model Browser to see the results of the different meshing options.

Note that the non-aligned standard mesh tends to be more orthogonal following the direction of the cardinal axis. The Align option allows the mesh to flow with the contours 154 HMD Introduction


Chapter 3: 2D Meshing of the part and the addition of the size option controls the size of the elements more and results in less trias.

Step 7: Edge and Surface Deviation 1. Create 2 more component collectors called EdgeDev and SurfDev and make them distinct colors. 2. Organize a copy of all the surfaces into both collectors. 3. Make Current the EdgeDev collector and the only collector visible. 4. In the the 2D AutoMesh select the edge deviation sub.

5. Set the values as follows:

6. Mesh the part and if in interactive mode, finalize the mesh. Note how the mesh size varies depending on surfaces curvature. At rounded edges and around holes the mesh size drops down to the minimum element size to capture the curvature. Areas of no curvature are meshed at the largest element size.

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Chapter 3: 2D Meshing 7. Make Current the SurfDev collector and the only collector visible. 8. Select the surface deviation sub .

9. Set the values as follows:

10. Mesh the part. Note how now the mesh size is dependent on and varies with the curvature of the surfaces. Fillets between and areas of high surface curvature are captured with smaller elements but large flat areas are of a higher element size.

11. Experiment in these two sub s and determine how the interactive mesh controls can be used to enhance the feature capturing abilities of these meshing styles.




2 - Checking and Editing Mesh Once a mesh is created, HyperMesh has many tools for checking element quality and modifying the mesh to make it more desirable. These tools can be used at almost any point in the meshing process. This section is separated from sections on creating mesh so that the focus can be on checking and editing tools. In this section, you will learn how to: 

Identify shell element connectivity problems.



Correct shell element connectivity problems.



Review the model’s shell elements to ensure connectivity problems were corrected.



Re-mesh the elements along the rib.

Checking and Editing the Mesh: Tools These mesh editing tools can be found as follows: •

Mesh > Check > Nodes

•

Mesh > Check > Elements

•

Mesh > Edit > Elements

•

Mesh > Check > Components

•

View > Toolbars > HyperMesh > Checks Toolbar

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Nodal Connection 

Edges / T-connection 

or Mesh > Check > Nodes > Equivalence

Free edges are defined as a pair of nodes identifying an element edge that are not shared with another element. Free edges are normally found around the outer perimeter of a part or around openings within the part.

This allows to display free edges to T-connection in the model by creating 1D elements on each one. Free edges are displayed as red plot elements in their own component called êdges. Free edges within a field of elements typically indicate a discontinuity within the mesh. For free edges you can also equivalence nodes within a specified tolerance



Find  Tool page > find OR Display toolbar >



Chapter 3: 2D Meshing The Find allows you to locate entities in a database: • You can use the Find Entities sub to find individual elements in your model. When you find entities, you will often want to turn on the IDs, or save them to the mark. At the very least, when you find a hidden entity, it will be displayed. • The Find Attached sub finds entities that are attached to other entities. For example, after you have selected an element, you may use this function to view the elements that are attached to it, allowing you to move progressively through the model, row by row. The Find Attached sub allows you to find entities that are attached to geometry or FE entities. • The Between sub allows you to find entities that are shared by two or more of the selected entities. For example, you could find nodes that are shared between selected components or surfaces, and so on.

Element Quality Paramenters 

Check Elements  (F10)

or Mesh > Check > Elements > Check Elements

The Check Elements allows you to the basic quality of your elements and to the geometric qualities of those elements:

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Chapter 3: 2D Meshing o

Warpage: The amount by which an element or element face (in the case of solid elements) deviates from being planar. Warpage of up to five degrees is generally acceptable. Since three points define a plane, this check only applies to quads. The quad is divided into two trias along its diagonal, and the angle between the trias normals is measured.

o

Aspect: This is the ratio of the longest edge of an element to either its shortest edge or the shortest distance from a corner node to the opposing edge ("height to closest node"). Aspect ratio should be less than 5:1 in most cases.

o

Skew

o



trias: calculated by finding the minimum angle between the vector from each node to the opposing mid-side and the vector between the two adjacent mid-sides at each node of the element. Ninety degrees minus the minimum angle found is reported as the skew.



quads: calculated by finding the minimum angle between two lines ing opposite mid-sides of the element. Ninety degrees minus the minimum angle found is reported.

Chordal deviation is the perpendicular distance between the actual curve and the approximating line segments.




Cell Squish: The cell squish criteria describes the non-orthogonality of an element with respect to its faces for 3D elements or edges for 2D elements. It is defined as follows:

o

Length >: The elements that have a length greater than the values specified are highlighted when the length function is selected. These elements remain highlighted until you exit the Check Elems or you select another check element function. The shortest distance from a corner node to its opposing edge (or face, in the case of tetra elements); referred to as “height to closest node”.

o

Length <: The elements that have a length less than the values specified are highlighted when the length function is selected. These elements remain highlighted until you exit the Check Elems or you select another check element function.

o

Jacobian: A measure of the deviation of an element from an ideally shaped element. The Jacobian value ranges from 0.0 to 1.0, where 1.0 represents a perfectly shaped element. However, Jacobian values of 0.7 and above are generally acceptable. The determinant of the Jacobian relates the local stretching of the parametric space required to fit it onto global coordinate space. HyperMesh evaluates the determinant of the Jacobian matrix at each of the element’s integration points (also called Gauss points), and reports the ratio between the smallest and the largest.

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Equia Skew: Opens the equiangle skew utility. This utility is used to find the number of elements among those displayed that have a normalized equiangle skew larger than the value specified. The normalized equiangle skew is defined in the following way:

o

Area Skew : The area skew criterion describes the deviation of an elements with respect to an “optimal” elements. A circle is generated through the three corner points of the actual triangle. This circle defines a ideally shaped tria elements, from which the area is computed, A_ideal. The area from the actual triangle is computed as well, A_actual. The area skew is defined as: Area skew = (A_ideal-A_actual) / A_ideal.

o

Taper: 

quad (quadrilateral element): is defined by first finding the area of the triangle formed at each corner grid point. These areas are then compared to one half of the area of the quadrilateral.



Chapter 3: 2D Meshing HyperMesh then finds the smallest ratio of each of these triangular areas to ½ the quad element’s total area (in the diagram above, "a" is smallest). The resulting value is subtracted from 1, and the result reported as the element taper. This means that as the taper approaches 0, the shape approaches a rectangle.



o

tria (triangles): are assigned a value of 0, in order to prevent HyperMesh from mistaking them for highly-tapered quadrilaterals and reporting them as "failed".

Interior Angles 

tria min/max angle: The minimum/maximum allowable interior angle for a tria element.



quad min/max angle: The minimum/maximum allowable interior angle for a quad element

Element Normals 

Normals 

or Mesh > Check > Elements > Normals



The Normals allows you to display and reverse the normals of elements or surfaces.



The orientation of element normals can also be adjusted. The normal of an element is determined by following the order of nodes of the element using the right-hand rule.



Normals can be reversed for both surfaces and elements. For elements there is an option to adjust the selection to a reference element, by selecting it with the elem selector and clicking the adjust normals button.



For normal review, you can select between two modes: Normals can be reviewed showing a vector (positive normal direction) or by colors (color mode shows the positive side of a shell or surface in red and the negative side in blue).

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Free edges are defined as a pair of nodes identifying an element edge that are not shared with another element. Free edges are normally found around the outer perimeter of a part or around openings within the part.

Checking & Editing 2D Mesh 

Quality Index  Mesh > Cleanup Elements > Quality Index OR



Quality Index  Mesh > Check > Elements > Quality Index 

The Quality Index allows you to calculate a single value to represent the quality of the displayed shell (2-D) model. Criteria settings are stored and retrieved using a criteria file. Results from the Quality Index (QI) can be saved to a summary file. Edit nodes and elements interactively or by automatically maximizing element quality.



Chapter 3: 2D Meshing  There are no subs on the Quality Index , but there are three pages of criteria accessed via the page arrow buttons.  While in the QI , elements are colored according to how well they adhere to pre-set quality requirements, rather than according to their component or any other visualization mode chosen.



The Quality Index value is a function of twelve criteria with -defined weight factors. Each criterion has five rating levels. Each element is assigned a penalty depending on where they fall and is assigned the corresponding element Q.I. color.



The compound Q.I. displays on the right-hand side of the , along with the number and percentage of elements that failed a quality check. This portion of the also includes a slider control that allows you to highlight elements falling at or below a certain quality level, and a group of buttons to access cleanup tools (secondary , where you can manually alter the placement of nodes to improve local quality) and save a list of failed elements.



The left-hand portion of the Quality Index consists of three pages; the current page number displays in the upper-left corner of the . To either side of the page number, a small arrow button allows you to page forward or backward to view the other pages. In addition, one column on pages 1 and 2 includes a toggle at the column heading; use this toggle to switch the column between displaying the worst quality value found for each quality check, or the total Q.I. value generated by each check.

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

o

Page1

o

Page2

o

Page3

Page 1-2-3  Cleanup tools It opens the temporary QI cleanup tools secondary , where you can manually alter the placement of nodes to improve local quality.






Page 1-2  Patch Checker



Page 3  Summary & edit criteria… o

Summary - You can save the quality results of the selected model to this file (summary file). It exports the information seen in the results pages of this . In addition, it records the IDs of the three elements that have the worst quality result for each criterion.

o

Edit criteria… - Click this button to open the criteria file editor, from which you can load, save, and modify files that contain the criteria used by the Quality Index

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Chapter 3: 2D Meshing 2D Mesh Quality Report 

HTML Mesh Quality Report  Mesh > Check > Elements > Quality Report o

Quality Report - Current Model or Multiple Models

o

Summary page - “Dashboard” of results and Links to each report page

o

Report page for each model - Detailed QI values, Link to criteria &model file

Contour by Element Quality



Perpetual Quality Index visualization mode



Global and local criteria mode



Interactive editable settings in both global and local mode




2D Remeshing 

Automesh > 2D Remeshing - This option in automesh allow you to remesh directly a selected group of elements  switch from surfs to elems

 In HyperMesh there are options to remesh elements using the “automatic feature detection”, “features” or the new option “lines”.  Using any free form line, the automesh functionality will remesh ensuring that there is nodal seeding along the selected line. The nodal seeding can be adjusted as required  Meshing regions where tight control over mesh flow or mesh density will benefit from this functionality. Other use cases will also include defining weld/adhesive lines

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Chapter 3: 2D Meshing 2D Automeshing – QI Optimize 

Automesh > QI optimize Options

Checking & Editing 2D Mesh - Other s 

Create 2D Element  Mesh > Create > 2D Elements > Elements






Edit 2D/3D Element  Mesh > Edit > Elements > 

Combine – merges 2 or more elements into 1 single element

 Split – draws a line to cut elements  Detach – disconnects selected elements from other elements  Imprint  Extend  …

 Replace  Mesh > Replace (F3)  Merge 2 nodes into 1 node (elements are now connected)

HyperWorks 13.0



Exercise 3b - Refining Topology to Achieve a Quality Mesh Step 1: Open the model file, 03b-2D-MESH-EDIT-CHECK.hm. The model for this exercise is 03b-2D-MESH-EDIT-CHECK.hm. Take a few moments to observe the model using the different visual options available in HyperMesh (rotation, zoom, etc.).

Step 2: Create a preliminary mesh. 1. From the menu bar, click Mesh > Create > 2D AutoMesh to open the Automesh . 2. Set the selector type to surfs. 3. Go to the size and bias sub-. 4. In the element size = field, type 2.5. 5. Set mesh type: as mixed. 6. Switch the meshing mode from interactive to automatic. 7. Click surfs >> displayed. 8. Deactivate the flow: > align and size options.

9. Click mesh to mesh the surfaces.




Initial mesh on the defeatured clip model

Step 3: Review the mesh quality. 1. Take a minute to rotate, zoom, and pan the model to review the mesh that was created. Note the locations where the mesh was not created in rows and columns of quads. 2. From the menu bar, select Mesh > Check > Elements > Check Elements to open the Check Elements . 3. Go to the 2-d sub-. 4. In the length < field, type 1.

5. Click the length< button to evaluate the minimum length. 6. Note the elements that failed the check. The topology will be edited to correct of some of these, leave the rest as is. 7. Click return to exit the .

Step 4: Remove short edges by combining fixed points. 1. From the menu bar, click Geometry > Quick Edit > replace point: to open the . 2. that the active selector is set to point(s). 3. Select the lower fixed point as indicated in the following image (point to move). 4. Once the point is selected, activate the retained button. HyperWorks 13.0


Chapter 3: 2D Meshing 5. Select the upper fixed point as indicated in the following image (point to retain). 6. Once the second point is selected, click replace.

Selecting fixed points to be combined




Step 5: Remove the fixed point interior to all surfaces. You should still be in the Quick Edit . 1. Go to add/remove point: 2. Select (mouse button: right click) the four fixed points as shown in the following image. Each fixed point will be deleted as you select it. These fixed points are left over from a defeaturing operation where small holes (pinholes) were removed. They could remain without greatly sacrificing the element quality, given the element size used for the mesh, but the mesh should be better without them.

Fixed points to be removed

HyperWorks 13.0




Step 6: Add edges to the surfaces to control the mesh pattern. You should still be in the Quick Edit . 1. Go to split surf-line: 2. Zoom into the area indicated below and select the indicated fixed point as node. 3. With the active selector now on line, select the line shown in the following image. Once both the point and line are selected, an edge will be created from the location of the fixed point perpendicular to the line and the mesh will be modified accordingly.

Select fixed point and line to split the surface.




4. Repeat sub-steps 6.2, 6.3 for the following point and line.


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Chapter 3: 2D Meshing 6. Repeat sub-steps 6.2, 6.3 for the following point and line.


7. Repeat sub-steps 6.2, 6.3 for the following point and line.

Select fixed point and line to split the surface

Step 7: Add edges to the surfaces to control the mesh pattern. You should still be in the Quick Edit . 1. Go to split surf-line 178 HMD Introduction


Chapter 3: 2D Meshing 2. Zoom into the area indicated below and select the indicated fixed point as node.

3. With the active selector now on lines, select the edges shown in the following image (4 edges included in the rectangle).

Once both the point and line are selected, an edge will be created from the location of the fixed point perpendicular to the line, same for the other lines.

HyperWorks 13.0



Step 8: Suppress shared edges causing a small edge. You should still be in the Quick Edit . 1. Go to toggle edge: 2. Select each of the lines in the image below using your left mouse button and click line(s). Each line will become suppressed (blue) as you click line(s).

Surface edges to suppress by toggling

2. The mesh will be modified based on topology revision. 180 HMD Introduction



Step 9: Review the mesh quality. 1. Take a minute to rotate, zoom, and pan the model to review the mesh that was created. Note that the mesh now consists completely of rows and columns of quads. 2. Enter the Mesh> Check > Elements > Check Elements . 3. Go to the 2-d sub- 4. In the length < field, type 1. 5. Click the length button to evaluate the minimum length. Note the elements that failed the check. There are only two elements that fail the check, and these fail the check because of the shape of the part. However, they are not too small compared to the global element size, so you can leave them as they are.

6. Access the Mesh > Create > 2D Automesh . 7. Go to the QI optimize sub-. 8. that elem size = is set to 2.5 and the mesh type is set to mixed.

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Chapter 3: 2D Meshing 9. Click edit criteria. 10. In the Target element size field, type 2.500.

11. Click Apply and OK. 12. Select surfs >> displayed to select all displayed surfaces. 13. Click mesh. Note that the old mesh is replaced by the new mesh. [HINT] If there is a message saying, "There is a conflict between the requested element size and quality criteria ideal element size," click the button, Recompute quality criteria using size of 2.5. 14. Access the Quality Index by clicking Mesh > Check > Elements > Quality Index. 15. Go to page1 and that the comp. QI is 0.01. This low value indicates that the mesh is good quality. The higher the number, the lower the mesh quality.




Step 11 (Optional): Save your work. The part is now meshed and ready to be set up for an analysis. Save the model, if desired.

HyperWorks 13.0



Exercise 3c - Checking and Editing Mesh In this exercise, you will learn how to:    

Identify shell element connectivity problems Correct shell element connectivity problems Review the model’s shell elements to ensure connectivity problems were corrected Remesh the elements along the rib

Exercise This exercise uses the model file, 03c-2D-MESH-IMPRINT-EXTEND.hm.

Step 1: Retrieve and view the HyperMesh model file. Open the file 03c-2D-MESH-IMPRINT-EXTEND.hm

Step 2: Review the model’s free edges to identify shell element connectivity problems. 1. Access the Edges in the following ways: 

From the menu bar, select Mesh > Check > Components > Edges.



From the Checks toolbar, select the Edges icon (



Press SHIFT+F3 KEYS

)

2. With the comps selector active, click any element in the graphics area. The component containing the element is selected. 184 HMD Introduction


Chapter 3: 2D Meshing 3. Click find edges. Red, 1-D elements are displayed. They are organized into the new component named êdges. A red 1-D element is created along each shell element edge that is free; one or more of the element edge’s nodes is not shared by the adjacent elements.

Note: For a component name whose first character is ^, the component and its contents is not written to the input file when the model is exported. 4. Click Shaded Elements and Mesh Lines (

).

5. Observe the red, 1-D elements (free edges). 6. Try to identify gaps in the continuity of the mesh. Hint: Look closely at free edges interior to the model. 7. In the Model Browser, turn the display off for the component shells to continue to identify which red, free edges do not belong.

HyperWorks 13.0



8. Turn on the display for the component, shells.

Step 3: Solve the shell element connectivity issues using the Edges . 1. In the tolerance= field, type 0.01. 2. Select an element in the graphics area to select the component. 3. Click preview equiv. The status bar displays the following message: "81 nodes were found." A sphere, , is created on nodes having a distance between each other equal to or less than the specified tolerance. 4. Notice that for this exercise’s model, a sphere is not created on every node along all of the red, free edges, which do not belong. A larger tolerance must be specified to identify the rest of the nodes. 5. For tolerance =, increase its value until all 96 nodes are identified as shown in the following image. Be careful not to increase too much the tolerance value. Although the 96 nodes will be identified, an excessively large tolerance value may collapse elements when the identified nodes are equivalenced. To find out the maximum value that can be safely used for tolerance without collapsing the elements, press the F10 key to go to the check elems , go to 2-d sub and click length. The status bar will display ‘… The min length is 1.49.’ A tolerance value < 1.49 can safely be used, without causing any elements to collapse when identified nodes are equivalenced. Click return to go back to Edges .




The nodes identified with preview equivalence

6. Click equivalence. The 96 coincident nodes are equivalenced. 7. Rotate and observe the model to see that the mesh still looks as it should and no elements are collapsed. 8. Click delete edges. The red, free edges and their component, êdges, are deleted. Note: Remain in the Edges .

Step 4: Review the model’s free edges again to confirm that all of the shell element connectivity problems have been corrected. 1. Click find edges. Observe the red, 1-D elements (free edges). Are there any red, free edges that should not belong if the mesh was continuous or if all of the elements were connected? Hint: Only red, free edges should exist on the perimeter of the part and on periphery of internal holes. 2. Use the Model Browser to turn the display off for the component, shells, to observe that all of the free, red edges belong. 3. After ing that the model has correct red, free edges, click delete edges. HyperWorks 13.0



Red, free edges that belong

Step 5: Display the element normals and adjust them to point in the same direction. 1. Go to the Normals . The Normals can be accessed in the following ways: 

From the menu bar, select Mesh > Check > Elements > Normals



From the Checks toolbar, select the Normals icon (



Press the SHIFT+F10 keys

)

2. Choose the elements sub and set toggle to vector display normals. 3. With the comps selector active, select one element from the graphics area to select the component. 4. Click display normals. Arrows (vectors) are drawn from the element centroids and show the direction of the element normals. Notice the arrows do not all point from the same side of the part. For some analysis, the element normals should point the same side. 188 HMD Introduction



5. Click size = and enter the size which the normal should be in model units and select display normals again. When size = is set to 0, the vector will be 10% of the screen. 6. Toggle vector display normals to color display normals.

7. Click display normals. The element normals are displayed using colors. The red side of the elements is the positive normal direction, while the blue side is the negative normal direction.

HyperWorks 13.0


Chapter 3: 2D Meshing 8. Notice each side of the part shows red and blue. 9. Click the orientation: elem selector to make it active.

10. Select an element from the graphics area.

11. Click adjust normals. All elements on either side of the part are the same color, red or blue. The status bar displays the following message: "[X] elements have been adjusted."

If after adjusting the normals, there are still elements on one side of the part which are of different color, change to elems from comps for the entity selector, choose these elements and click reverse normals.




12. Click return.

Step 6: Review the quality of the elements using the check elems . 1. Access the check elems in one of the following ways: 

From the menu bar, select Mesh > Check > Elements > Check Elements



From the Checks toolbar, select the Check Elements icon (



Press the F10 key

)

2. Go to the 2-d sub. 3. that jacobian < field is set to 0.7. 4. Click jacobian to determine if any elements have a jacobian of less than 0.7. Elements having a jacobian of less than 0.7 are highlighted.

5. Notice that several elements on the triangular rib and around the smaller of the two holes have a jacobian of less than 0.7. HyperWorks 13.0


Chapter 3: 2D Meshing The status bar displays a message indicating how many elements failed this check. 6. In the graphics area, click an element. A window appears that lists each quality check result for the element.

7. Click the right or left mouse button to close the pop-up window. 8. On the right side of the , switch from standard to assign plot. 9. Click jacobian to review again. A legend for jacobian values appears and each element is colored accordingly. The red elements have a jacobian less than the threshold, 0.7.

10. that quads: min angle < is set to 45. 11. Click min angle to determine if any quad elements have an angle of less than 45.




12. Notice that a couple of elements on the rib have an angle of less than 45. 13. that the max angle > field is set to 135. 14. Click max angle to determine if any quad elements have an angle greater than 135.

15. Notice that several elements on the rib have an angle greater than 135. 16. Click return.

Step 7: Remesh the elements on the rib using the automesh . 1. Access the Automesh in one of the following ways:  

From the menu bar, select Mesh > Create > 2D AutoMesh Press the F12 key

2. that you are in the size and bias sub. 3. Switch the entity selector to elems. 4. Toggle to interactive. 5. For element size=, type 3.5. HyperWorks 13.0


Chapter 3: 2D Meshing 6. Select one rib element from the graphics area. 7. Select one element on the plane of elements perpendicular to the rib and in the same plane as the rib’s shortest edge as shown in the following image.

Example of elements to select 8. Select elems >> by face to complete the selection of elements as shown in the following image.

Elements selected using by face 9. Click mesh. The meshing module appears.




10. In the density sub, change the element density on the rib’s hypotenuse edge to 9. 11. Change the element density on the rib’s shortest edge to 5.

Adjusting element edge densities 12. Keep all other element edge densities the same. HyperWorks 13.0


Chapter 3: 2D Meshing 13. Access the mesh style sub. 14. Under mesh method, set the last option to free (unmapped). 15. Under mesh method, select set all.

16. Click mesh to preview the mesh. 17. Go to the checks sub, and check the jacobian, quads: min angle, and quads: max angle. 18. Notice that no elements fail the minimum and maximum angle checks. Only a couple of elements have a jacobian of less than 0.7. The smallest jacobian is 0.68, which can still be considered good quality.

19. Click return to accept the mesh and go back to the main menu.




Step 8: Use the smooth to adjust the node placement on the rectangular plane of remeshed elements. 1. Click Mesh > Cleanup Elements > Smooth to open the Smooth .

2. Go to the plates sub. 3. With the smooth: elems selector active, select an element on the rectangular plane of re-meshed elements. 4. Select elems >> by face.

HyperWorks 13.0


Chapter 3: 2D Meshing 5. For iterations = specify 10. 6. Switch the smoothing algorithm from autodecide to shape corrected. 7. Click smooth.

8. Click return.

Step 9: Remove tria elements from another area of the model using the edit element , split and combine subs. 1. On the 2D page, enter the edit element or Press the F6 key. 2. Go to the split sub.

3. With the splitting line: points selector active, click four screen points as shown the following image. Temporary line segments are drawn to connect the points. 4. You can right-click to undo the last line segment drawn or you can click delete line to start over with selecting points.




5. Click split. Elements that have the line through them are split. The resulting mesh should look like the mesh in the following image. There are two pairs of adjacent tria elements.

6. Go to the combine sub and set the toggle to combine to quad.

7. Select two adjacent tria elements as indicated in the following image. 8. Click combine. HyperWorks 13.0


Chapter 3: 2D Meshing 9. Repeat 11.7 and 11.8 for the other two adjacent tria elements. 10. Remain in the edit element sub.

Trias to select

Combining trias into quads

Step 10: Dynamically move nodes on the mesh area to improve element quality. 1. Go to the menu bar Mesh > Cleanup Elements > Element Cleanup, leave all options with default values. Select elems >> displayed.

2. Click cleanup to get an Element Quality Summary.

Click on continue, if you get the following message:



Chapter 3: 2D Meshing 3. Go to the Visualization toolbar and set visualization as By Element Quality. This permanent mode serves as a useful tool to investigate each specific element criteria, as well as evaluate the overall quality of a mesh. Element Quality View is a permanent visualization mode that HyperMesh displays in the upper left-hand corner of the graphics area when you select By Element Quality on the Visualization toolbar. Use this tool to investigate each specific element criteria, view a breakdown of all failed and worst elements, resolve all criteria violations at one time, and evaluate the overall quality of a mesh. When you select Element Quality View, HyperMesh displays the Multiple Criteria legend by default.

In this legend, you can:   

review the different 2D element criteria's adjust the initial threshold values assigned to each 2D element criteria select specific criteria's to investigate further

The Element Quality View tool bases the initial threshold values on the ideal, good, warn, fail (default), and worst values that are defined in the current 2D element criteria settings. By default, this tool bases the initial threshold values on the fail column. You can directly edit these values from the Element Quality View or you can edit them in the Criteria File Editor. Note: Any changes that you make in the Element Quality View will impact all of the other Element Quality View settings. The changes that you make to the threshold values in the Element Quality View will not affect the values in the criteria file, but any changes that you make to the criteria file will affect the Element Quality View. HyperWorks 13.0


Chapter 3: 2D Meshing When you click a criteria in the Multiple Criteria legend, a single criteria specific legend appears to the right of the threshold values. The elements are color coded according to how well they adhere to the quality requirements in the graphics area. In the graphic area, click on one of these criteria in the legend, it will appear another table for the selected criteria.

Each 2D element criteria, in the Multiple Criteria legend, has its own single criteria legend. The single criteria legends consists of a color coded sliding scale, which you can use to evaluate the elements in the graphics area and resolve all criteria violations. The colors exhibited in the sliding scale reflect the quality of each element in the graphics area. The elements that are of the best quality will always display in blue. The elements that are of the worst quality will always display in red. The Element Quality View tool determines the quality of each element using the 2D element criteria that you defined in the Multiple Criteria legend. The Element Quality View tool always lists the values in the sliding scale from low to high, with the lowest value always being at the bottom of the scale and the highest value always being at the top. This tool always defines the first and last values in the legend with the minimum and maximum values. The Element Quality View has Context Menus you can activate with a right-click on the Multiple Criteria legend.

Note: refer to online help to get more details. 202 HMD Introduction



Step 11: For the same area of elements you focused on in the previous step, optimize element quality by clicking nodes and elements. 1. Go to Mesh > Cleanup Elements > Quality Index and select cleanup tools.

2. With the node optimize selector active, click a few nodes of the mesh area you modified.

HyperWorks 13.0


Chapter 3: 2D Meshing When a node is clicked, it is repositioned so that the elements attached to it have the best possible quality based on the criteria specified in the qualityindex . 3. Click the selector element optimize to make it active.

4. Click yellow elements in the mesh area with the red circle shown below.

When an element is clicked, it is adjusted to have the best quality possible based on the criteria specified in the qualityindex . When you click a red element, it may become yellow or the background color (no color assigned). When you click a yellow element, it may become the background color (no color assigned).




Step 12: Add a ring of radial elements around the smaller of the two holes. 1. Click the Utility tab. If the Utility Menu is not displayed in the HyperMesh session, go to View menu > Browsers > Hypermesh > Utility. 2. On the Geom/Mesh page, click Add Washer.

3. The Add Washer along a Circular Holes dialog box will be opened. 4. With the nodes selector active, select one node on the edge of the smaller hole as indicated in the following image.

Example node to select 5. Click proceed. A pop-up window for Add Washer along a Circular Hole utility appears. 6. Toggle to Width, and for Value specify 3.0. HyperWorks 13.0


Chapter 3: 2D Meshing 7. Select the Minimum number of nodes around the hole check box. 8. In the Density: field, enter 12.

Add Washer along a Circular Hole dialog box

9. Click Add. 10. Click Close. The mesh around the hole should look like the mesh in the following image.




Resulting mesh around the smaller hole

Step 13: Imprint Mesh to different destinations. 1. Open Model Browser and select IMPRINT component, right-click on it and select Show. 2. Go to Mesh > Edit > Elements > Imprint sub. The imprint sub allows you to cause mesh from different, overlapping components to sync or line up with each other, in order to facilitate better connection modeling between them. 3. Select component IMPRINT as source, Select component shells as destination and select destination for remain: option. This tool takes existing elements and/or components and can be imprinted into elements and/or components, changing direction and destination.

HyperWorks 13.0



Original: Violet elements are offset from yellow.

4. Select create.

Violet source elements are imprinted in destination (yellow).

5. Select reject. 6. Select component IMPRINT as source, Select component shells as destination, select destination for remain: option and make sure to flag option elems to destination comp.




Violet source elements are imprinted in destination (yellow), element organized into yellow component.

7. Select reject. 8. Select component IMPRINT as source, Select component shells as destination, select source for remain: option and make sure to flag option elems to destination comp.

Yellow destination elements are imprinted to Violet elements, element organized into yellow component.

9. Select reject and return.

Step 14: Extend Mesh to different destinations. 1. Open Model Browser, select IMPRINT component, right-click on it and select Hide. Select EXTEND component, right-click on it and select Show. 2. Go to Mesh > Edit > Elements > Extend sub. The extend sub allows you to create smoothly-meshed connections between different components that do not quite touch, but are meant to. Mesh can be imprinted such that both components are remeshed to match, or the source comp is remeshed to HyperWorks 13.0


Chapter 3: 2D Meshing match the destination comp, or vice-versa. In addition, you can actually merge the elements of the source component into the destination component altogether. 3. Select nodes by windows (see red rectangular area in the following picture) from EXTEND component (source), select component shells as destination and select along vector for projection: option (select N1 and N2 as shown in the following picture, red circular area) to define direction.

4. Select create. The resulted mesh, as shown in the following picture, connects the 2 parts with just 1 element along the projection, the remesh extension option is deactivated.




5. Select reject. Repeat step 14.3 and 14.4 with the same options and selections, just make sure to flag on remesh extension option. The resulted mesh, as shown in the following picture, connects the 2 parts with remeshed elements along the projection, the remesh extension option is activated.

Step 15 (Optional): Save your work. With this exercise completed, you can save the model if desired. HyperWorks 13.0



3 – Comparison Tool Geometry > Check > Surfaces > Comparison OR Mesh > Check > Elements > Comparison.

Note: Currently, only surfaces and 2D elements are ed in the Comparison tool.

• Use the Comparison tool to perform a model-based CAD-CAD, CAD-FE or FE-FE comparison between two models, or two selections of entities. You can also use this tool to find and report on geometrical/shape differences. When you are comparing entities, the entities must exist in the HyperMesh database.

• The Comparison tool generates results by comparing the source entities to the target entities. Currently, only 2D elements are ed for the Comparison tool. The results generated by this tool can be broken down into the following categories: Matches, Overlapped, Intersected, and Unmatched.




4 - Batch Meshing Geometry cleanup and meshing are often cited as time consuming aspects of finite element modeling. In HyperMesh, these tasks can be performed in batch mode with the BatchMesher, requiring a minimum of input and interaction. This section walks the through the basic process of meshing a part using the batch mesher. In this section, you will learn how to: 

Define a configuration for the batch mesh



Edit the criteria and parameter files



Run the batch mesh job



Monitor and review the batch mesh job

Batchmesher BatchMesher tool  Start menu, select the Altair HyperWorks [Version] > BatchMesher •

BatchMesher is a tool that performs geometry feature recognition, cleanup and automatic meshing in batch mode for given CAD files.

•

BatchMesher uses criteria set by you to determine the quality index (QI) of a model.

•

Final results are stored in a HyperMesh binary database file containing both the cleaned-up geometry and the resulting finite element mesh.

•

The required inputs are set within a parameter file (average element size&type and geometry features) and a criteria file (target element quality requirements like Jacobian, warpage, …).

•

-defined Tcl procedures can also be supplied to perform both run-based (prerun, post-run) as well as model-based (pre-geometry load, post-geometry load, prebatchmesh, post-batchmesh) customizations.

HyperWorks 13.0



Batch Meshing Process and Required Input 1. Configurations tab  Create / specify Configurations 

Mesh Type  Combination of element criteria and geometric parameters.



Parameter File  is used to setup the geometry cleanup and defeaturing parameters. These parameters are used to define things such as washer layers around holes, defeaturing pinholes and solid holes, rows of elements along fillets, and many other options.



Criteria File  is used to setup the quality index (QI) mesh criteria. This criteria is used in QI and batch meshing, and in QI-based element checks. Criteria definitions can be saved to a file, and loaded for subsequent editing.



Criteria and Parameter File can be edited with the Editor o

Select 1 Criteria or Parameter file form the table e click on the Edit File icon



.

Mesh Type  Parameter & Criteria File  Element criteria & geometric parameters combination.




HyperWorks 13.0



2. Procedures tab  and specify Procedures (optional) 

BatchMesher can be customized by providing -defined Tcl procedures that run at specific times during the BatchMesher process



Procedures can be customized for:



o

Pre-run – (Executed before the first model/job starts)

o

Post-run – (Executed after the last model/job completes)

o

Pre-geometry load - (Executed immediately after the job begins, before the input model is imported)

o

Pre-batch mesh – (Executed immediately after the input model is imported, before the batch mesh begins. Examples include extracting a midsurface or performing a surface offset)

o

Post-batch mesh - (Executed immediately after the batch mesh process is complete. Examples include creating solver specific cards, or exporting the mesh in a specific format

These scripts can perform a wide range of tasks. Some examples include: o

Exporting a mesh in solver format

o

Generating the midsurface of a thin solid geometry

o

Performing a surface offset to move a sheet geometry to a midsurface location

o

Naming and numbering parts to -specific requirements




3. Run Setup tab  Set up the BatchMesher job 

This tab defines a batch mesh run and the jobs it contains. A table layout is used to specify each job, along with options that apply to the entire run. o Specify an input model directory where geometry files are located o Set Geom Type  Select geometry files from the directory o

Set Mesh Type  Select a configuration to use for the mesh type for each file

o

(OPTIONAL) Set Pre-Geom Load, Pre-Mesh, Post-Mesh Specify any procedures to be performed on each part.

o Specify an output directory where the meshed files will be located o Submit the batch mesh job

HyperWorks 13.0


Chapter 3: 2D Meshing 4. Run Status tab  Monitor the Run Status of the job 



Once a BatchMesher run is initialized, this tab reports on the status of the run and its jobs. o

Use the Run Status tab to keep track of all your submitted jobs

o

Use Load Mesh button to select a single job from the tree and use this button to invoke interactive HyperMesh and load the final batch meshed model. The corresponding criteria file is also loaded in the QI so that the quality checks represent the meshing requirements set in BatchMesher. This can only be performed on models that have a status of Done.

The Status can have one of 4 values: o

Working  Batch meshing is currently being performed on this model

o

Pending  This model is currently in the queue and has not started the BatchMesher process yet. Any models with the status can be canceled

o

Waiting  The job will begin automatically at a -specified date and time

o

Done  The batch meshing process is complete, and results can be reviewed.



Chapter 4: Solids & 3D Meshing

Chapter 4

Solids and 3D Meshing 1 - Creating and Editing Solid Geometry HyperMesh has several functions that require the definition of a volume, such as creating tetrahedral and hexahedral meshes. This can be done either with surfaces that enclose the volume, or with solid geometry entities. Working with solids provides a couple of advantages over surfaces. Selecting the volume for the function requires only a single click because solids represent the volume with a single entity, as opposed to surfaces. Solids that are topologically connected to each other also allow the functions being used to recognize the connection. Creating mesh in these cases allows the mesh in adjacent volumes to automatically have proper connectivity. In this section, you will learn: 

What is solid geometry



What is topology



What does 3D topology look like

Solids are geometric entities that define a three-dimensional volume. Geometric entities are defined as follows: 

Point: 0 dimensional; has only x, y, and z coordinates



Line: 1-dimensional; has length, can be curved through 3-dimensional space



Surface: 2-dimensional; has an area



Solid: 3-dimensional, has a volume

Solid Geometry HyperMesh s the same solid geometry that is created in popular CAD software. Solid geometry can be achieved through the importation of native CAD data or can be easily created from bounding surfaces using the Bounding Surfaces Geometry > Create > Solids > Bounding Surfaces. HyperWorks 13.0

option from the



Additionally HyperMesh has numerous solid geometry creating tools to assist in the manipulation of solids. These can be found through the pull-down menu, Geometry > Create > Solids.

Solids •

Creates solid geometry of basic shapes: •

Square / Block - Cylinder / Cone – Sphere – Torus

•

Full or Partial

•

Bounding Surfs – Select surfaces that enclose a volume

•

Drag along vector– “Extrude" a cross section along a a defined vector

•

Drag along normal– “Extrude" a cross section along surf normal vector

•

Drag along line– “Extrude" a cross section along a line

•

Spin – “Extrude” a cross section via a circular path

•

…




Solid Editing Tools for editing geometry: 

Surfaces o

Creates surfaces using various methods (Geometry > Create > Surfaces)

o

Can be used to split a solid (Geometry > Quick Edit) 



Edges of the surface must be equivalenced to edges on the solid.

Solid Edit (Geometry > Edit > Solids)

o

Trim with… – splits a solid into 2+ solids using: 

Nodes



Lines



Planes/Surfaces

o

Merge – combine 2+ adjacent solids into a single solid entity

o

Detach – disconnects connected solids

o

Boolean – advanced trim & merge operations 

Union (Solid A + Solid B) – same as merge



Intersection (Solid A x Solid B) – keeps overlapping portions of 2 solids



Removal (Solid A – Solid B) – deletes the volume of one solid from another



Cut (Cut Solid A with Solid B) – trims one solid with another solid 

keeps both solids, but they no longer overlap

HyperWorks 13.0





Solid Dimensioning (Geometry > Edit > Solids > Dimensioning)

Solid Topology & Terminology Topology governs the connectivity of solids and thus the connectivity of the elements created from them. •

•

•

Bounding Faces: o

A bounding face is a surface that defines the outer boundary of a single solid.

o

Bounding faces are shaded green by default.

o

A bounding face is unique and is not shared with any other solid. A single solid volume is defined entirely by bounding faces.

Fin Faces: o

A fin face is a surface that has the same solid on all sides--that is, it acts as a fin inside of a single solid.

o

Fin faces are shaded red by default.

o

A fin face can be created when manually merging solids or when creating solids with internal fin surfaces.

Full Partitions Faces: o

A full partition face is a surface that defines a shared boundary between one or more solids.

o

Full partition faces are shaded yellow by default.

o

A full partition face can be created when splitting a solid or when using Boolean operations to multiple solids at shared or intersecting locations.




Tools for Viewing Solids 3D Topology visualization can be controlled using the Visualization Toolbar > Visualization Options

In the HyperMesh Visualization toolbar, the Visualization Options Icon Visualization tab  Topology icon

will open the

.

•

Display or hide 2D and 3D topology (free, shared, t-junctions, suppressed edges) based on its type

•

Control surface transparency

•

Display 3D mappability with different shading colors related to Mappable solid regions.

HyperWorks 13.0



Geometry Color Mode Geometry Color Mode topology or by mappability.

to color geometry by component color or by




2 - Tetra Meshing Introduction to Tetra Meshing HyperMesh provides several methods of generating a tetrahedral mesh. The standard method creates tetras from an enclosed volume of shell elements, plus several parameters. This provides the with a lot of control over the final tetra mesh. The volume tetra mesher quickly and automatically creates a tetrahedral mesh on an enclosed volume of surfaces or solid geometry with only a few inputs. Finally, the quick tetra mesh creates a tetra mesh that maintains specified quality requirements, but may sacrifice details in the shape of the part to do so. All methods are valid in certain situations. The exercise in this section focuses on the standard and volume tetra meshing methods. In this chapter, you will learn about: 

Volume tetra mesher (Mesh > Create > Tetra Mesh > Volume tetra)



Standard tetra mesher (Mesh > Create > Tetra Mesh > Tetra mesh)



Checking tetra element quality



Re-meshing tetra elements

Volume Tetra Meshing The volume tetra meshing utility, found in the pull-down menu Mesh > Create > Tetra Mesh > Volume tetra sub-. •

The Tetra Mesh allows you to fill an enclosed volume (bounded by a shell mesh, tria and/or quad elements) with first or second order tetrahedral elements.

•

Use the Volume Tetra sub as a quick method to generate a shell mesh and fill the enclosed volume with solid elements. o

You can choose to create a shell mesh (2-D) using quads, trias, or mixed elements and a solid mesh (3-D) using tetrahedral elements only or mixed (tetras and penta) elements.

HyperWorks 13.0



Two options are available to control the mesh: 

Use Proximity – Creates smaller elements next to small features to make a smooth transition from small to large elements.



Use Curvature – Will place more elements along curved surfaces based on specified settings.

Standard Tetra Meshing The standard method of Tetra Meshing can be found through the Mesh > Create > Tetra Mesh pull-down menu and then select the Tetra mesh sub. Use the Tetra Mesh sub to fill an arbitrary volume, defined by its surface using tria/quad elements, with tetrahedral elements.



Requirements for the shell mesh: 

In general you need an enclosed volume (no free edges in the outer faces).



Tetra generation process should handle T and free edges inside the volume without problems. The regular tetrameshing can fail if the baffle connectivity is too complex.



There can be no duplicates in the mesh.



Elements should not fold over and overlap each other.



Avoid very low minimum tria angles.



Avoid a large difference in size between adjacent elements.



Avoid a large difference in size between two sides of a wall thickness.






For quad elements in the shell mesh: 

Split quads into 2 trias and create tetra elements under them - OR –

 

Keep the quad element and create pyramids under them

Process: 

Generate a surface mesh of shell elements



Check quality and connectivity of the plate elements



Generate the tetrahedral mesh



Delete the original surface mesh



Edit if necessary to obtain good quality

When using the Standard Tetramesh, the will select the trias/quads that will define the mesh and optionally the can select fixed trias/quads. HyperMesh will, when creating the tetra mesh, flip the diagonal of the 2D elements if it deems the resulting tetra mesh will be of a higher quality with the flip. HyperMesh will not do this to elements selected in the fixed selection. 

Floatable Trias/Quads 



Adjacent tria faces on the tetrahedral mesh may have their diagonal reversed from the shell mesh if tetras are better quality

Fixed Trias/Quads: 

Adjacent tria faces on the tetrahedral mesh always match the shell mesh

HyperWorks 13.0





Fix Comp Boundaries: 

If the float option is chosen for some boundary regions, HyperMesh is allowed to swap surface shell edges during mesh generation. However, this prevents the swapping of edges between two components.



Mesh to File:



Check 2D Mesh:




•

Example about Tetramesh with Edges and T connection: •

Geometry: 2 closed volumes of surfaces, the red one has T and Free Edges.

•

2D and 3D Tetramesh respect Free Edges and T connection.

HyperWorks 13.0



Tetra Remeshing Tetra Mesh  Mesh > Create > Tetra Mesh > Tetra remesh sub- Use the Tetra Remesh sub to regenerates the mesh for a single volume of tetrahedral elements. The Free boundary faces option affects those faces of tetra elements which are on the outside of the volume, meaning the tetra faces which have only one tetra attached. Those faces are called free boundary faces.



fixed: The free boundary faces are fixed.



swappable: The edges of the free boundary faces can be swapped. The mesh nodes stay unchanged.



remeshable: The free boundary faces will be remeshed.




Tetramesh Parameters Tetra Mesh  Mesh > Create > Tetra Mesh > Tetramesh parameters sub- Use the Tetramesh Parameters sub to set general qualities of the tetrameshing engine, such as a maximum element size, growth rate, the balance between speed and element quality, or whether to perform smoothing operations after initial meshing.

Refinement Box Tetra Mesh  Mesh > Create > Tetra Mesh > Refinement box sub- Use the Refinement Box sub to define a specific box-shaped volume within an existing tetramesh in which to generate finer mesh.

HyperWorks 13.0



Tetra Mesh Optimization tool In order to improve Tetrahedral Element quality, you can use the following tool from: Menu Bar > Mesh > Check > Elements > Tetra Mesh Optimization

Use this tool to modify an existing tetramesh, either by moving nodes or remeshing, to meet required parameters. One function is to remove sliver elements--tetrahedral elements which are so flattened that all of their nodes are very close to planar. If the element's Aspect Ratio (the ratio of its maximum length to its minimum length) is high, the element is a sliver; otherwise, it is a wedge.

This sliver is nearly flat in the horizontal plane, while this wedge is nearly flat in the vertical plane.

When you click Tetra Mesh Optimization, you will first be prompted with a temporary to select a set of elements to fix. 232 HMD Introduction



There are many criteria that you can consider in fixing such elements, each of which is drawn from the Editor Criteria… 

Tetra Mesh Optimization window > Optimize tetras by:

o

Editor Criteria… , this will open the Criteria File Editor to change the element quality requirements.

HyperWorks 13.0





Tetra Mesh Optimization window > Triangles:



Tetra Mesh Optimization window > Constraints: o fix shell comp boundariesall option. o maintain geometry edges option. o Max tetra size o Min tetra size o …






Tetra Mesh Optimization window > Check, to examine the mesh and count the number of bad elements, according to the criteria supplied (Jacobian, Volume Skew, etc.) The results display in the Status: area.



Tetra Mesh Optimization window > Show Failed to isolates only the failed elements in the graphics area



Tetra Mesh Optimization window > Apply to begin the fix process. The mesh is scanned and the program will try to fix as many elements as it can in accordance with the specified settings and criteria. You can abort the fix attempt early by clicking holding down the right-mouse button. Note that there can be a significant delay before HyperMesh finishes its current fix attempts and stops processing. The results are shown below:

HyperWorks 13.0





Tetra Mesh Optimization window > Refer to Online help to get more details.




Exercise 4a - Tetra Meshing Step 1: Load the model 1. Load the model 04a-VOLUME-TETRA-MESH.hm

Step 2: Attempt to TetraMesh the part 1. From the menu bar, enter the Tetra Mesh to create a 3D Tetramesh.

2. Select the Volume tetra sub . 3. Change the enclosed volume switch to surfs. 4. Attempt to select a surface on the model. (Note: You will not be able to.) With a properly enclosed model, the Volume tetra sub- will automatically select the entire volume and allow a mesh to be created. With the model now in a topological display mode, you will note there are many issues with the topology of the model. Only a fully enclosed volume can be properly tetrameshed, so we need to fix the model.

HyperWorks 13.0



Step 3: Fix the geometry topology. 1. Using the Geometry menu in the menu bar, use the geometry cleanup tools to ensure a fully enclosed volume. Hints: Equivalence and Toggle will solve most of the problems. Some issues require filler surfaces and point replacement. that topology visualization can assist in finding problems. The main tool to use is Geometry > Quick Edit 2. Check the Topology with the following tool, if you still have free edges and if you now a closed volume of surfaces. Select the Visualization Options icon and edges.

Step 4: TetraMeshing With a properly enclosed volume you can now create the TetraMesh 1. From the menu bar, enter the to create Tetramesh.

2. Select the Volume tetra sub 3. Change the enclosed volume switch to surfs. 4. Select a surface on the model. HyperMesh will automatically select all of the surfaces that enclose the volume. If this fails, there are still errors in the volume and need to be corrected using the geometry cleanup tools. 5. Leave all the default values and enter 4 into the element size= field. 6. Click on mesh to mesh the part. The part should now look similar to this:




7. Mask

half part to see the Tetrahedral Element structure.

8. Now delete the mesh.

Step 5: Using Proximity and Curvature Options Proximity and Curvature options can provide a mesh that adheres closer to the geometry in areas of curvature or small cross sections. 1. From the Volume tetra sub, select the part and select the Use proximity and Use curvature options 9. Set the following fields to the values shown: HyperWorks 13.0



10. Click on mesh to mesh the part.

Note the areas of curvature have a smaller mesh size to better capture the geometric curvature. 11. (Optional): Mask

half part to see the Tetrahedral Element internal structure.




Step 6: Check and Improve the mesh quality. To improve the overall Tetrahedral Element quality we will check the tet collapse value of the elements. Tetra elements whose collapse value falls below the value specified are highlighted when the tetra collapse function is selected. These elements remain highlighted until the Check Elems is exited. HyperMesh calculates tetra collapse by the following procedure. At each of the four nodes of the tetra, the distance from the node to the opposite side of the element is divided by the square root of the area of the opposite side. The minimum value found is normalized by dividing it by 1.24, and then reported. As the tetra collapses, this value approaches 0.0. For a perfect tetra, this value is 1.0. 1. Find the Mesh > Check > Elements > Check Elements option from the menu bar. 2. Select the 3-d sub-. 3. Enter 0.3 into the tet collapse< field and click the tet collapse button.

Note the number of failed elements in the dialog bar; the value should be around 111 elements.

4. Save the failed elements by selecting save failed. 5. Select the switch

and choose the option assign plot , click on tet collapse to view a contour map of 3D Tetra Collapse.

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6. In order to improve Tetrahedral Element quality, you can use the following tool from: Menu Bar > Mesh > Check > Elements > Tetra Mesh Optimization

Use this tool to modify an existing tetramesh, either by moving nodes or remeshing, to meet required parameters. One function is to remove sliver elements--tetrahedral elements which are so flattened that all of their nodes are very close to planar. If the element's Aspect Ratio (the ratio of its maximum length to its minimum length) is high, the element is a sliver; otherwise, it is a wedge.

This sliver is nearly flat in the horizontal plane, while this wedge is nearly flat in the vertical plane.

When you click Tetra Mesh Optimization, you will first be prompted with a temporary to select a set of elements to fix. 7. Select elems > displayed and click on proceed.




8. A Tetra Mesh Optimization window opens which contains the tools and settings for fixing slivers and wedges. The utility also has the ability to constrain trias, feature lines, nodes or elements within a refinement box.

There are many criteria that you can consider in fixing such elements, each of which is drawn from the Edit Criteria… 9. Click on Edit Criteria…, this will open the Criteria File Editor to change the element quality requirements. 10. Select Tetra Collapse, Vol Skew and Aspect Ratio, as shown below.

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11. Click on Apply and OK. 12. You’re again in the Tetra Mesh Optimization window. 13. The 3 previous criteria are selected in the Optimize tetras by: section.

14. In the Triangles: section, select the following, as shown also in the picture below: 

Fix all option.




15. In the Constraints: section, select the following, as shown also in the picture below: 

fix shell comp boundaries option.



maintain geometry edges option.



Max tetra size, enter 4



Min tetra size, enter 0.8



Leave the other options with default values

16. Click on Check button, to examine the mesh and count the number of bad elements, according to the criteria supplied (Jacobian, Volume Skew, etc.) The results display in the Status: area.

17. Click on Show Failed to isolates only the failed elements in the graphics area.

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18. Click on Apply to begin the fix process. The mesh is scanned and the program will try to fix as many elements as it can in accordance with the specified settings and criteria. You can abort the fix attempt early by clicking holding down the right-mouse button. Note that there can be a significant delay before HyperMesh finishes its current fix attempts and stops processing. The results are shown below:

19. If the results of the fixes are acceptable, click on Close to exit from Tetra Mesh Optimization utility 20. If the results of the fixes are unacceptable, click Reject to revert the mesh to its pre-fixed state. NOTE: You can only undo one fix operation this way--you cannot "back up" more than one step! 21. Click on to unmask all elements. 22. Refer to Online help to get more details. 23. Delete the mesh. 24. Go to Step number 8.




[OPTIONAL] Step 7 (from Step6-point5): Other methods to check and improve the mesh quality 1. Use Geometry Cleanup tools and Tetra remesh functions to try to achieve the best possible mesh. Experiment with different techniques and discover the results. To improve the overall Tetrahedral Element quality we will check the tet collapse value of the elements. Tetra elements whose collapse value falls below the value specified are highlighted when the tetra collapse function is selected. These elements remain highlighted until the Check Elems is exited. HyperMesh calculates tetra collapse by the following procedure. At each of the four nodes of the tetra, the distance from the node to the opposite side of the element is divided by the square root of the area of the opposite side. The minimum value found is normalized by dividing it by 1.24, and then reported. As the tetra collapses, this value approaches 0.0. For a perfect tetra, this value is 1.0. 2. Go to Mesh > Check > Elements > Check Elements. 3. Select the 3-d sub . 4. Enter 0.3 into the tet collapse< field and click the tet collapse button.

Note the number of failed elements in the dialog bar. The value should be around 111 elements.

5. Save the failed elements by selecting save failed. 6. Select the switch

and choose the option assign plot , click on tet collapse to view a contour map of 3D Tetra Collapse.

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7. Isolate the failed elements Failed elements can be isolated on the screen anytime using the following procedure. A. Go to the mask function. B. Click the elems button. C. Select retrieve. D. Click the elems button again. E. Select reverse. F. mask the elements. 8. Using the unmask adjacent button surrounding the failed elements.

twice to retrieve two layers of elements

9. In the tetramesh select the Tetra remesh sub. 10. Select the displayed elements and remesh them.

11. Check the tet collapse again and note the number has dropped. Many of the remaining 8 drops in this number. 12. Delete the mesh.




Step 8: Defining Mesh Patterns In instances where the needs to define a specific mesh pattern for surfaces or features, the volume tetra function can incorporate that pattern into the created tetra mesh. 1. Mesh the flat ring area with an element size of 1 and type of R-Tria.

Set all edges to 60 elements. The resulting mesh pattern should look similar to the one below.

2. Create a new volume tetra mesh, this time selecting the match existing mesh option. Make sure to set the tetra element size back to 4.

3. Note the Tetra Mesh has incorporated the defined mesh pattern. HyperWorks 13.0






Tetra Meshing Process Manager The Process Manager is a step-by-step tool providing a checklist of procedures to allow the to quickly organize and tetmesh a geometric model. Each step is provided in a hierarchal list providing the order in which the process needs to be performed and providing specialized tools at each step to simplify the process. These steps, while they can be done manually, can be performed in the TetraMesh Process Manager  Mesh > Create > TetraMesh Process pull-down menu and then select the Create New template in a much reduced timeframe.

In this section, you will learn ing the TetraMesh Process Manager to:       

Import geometry or an HM File Clean up the geometry Organize the model (holes and features) Establish mesh size and pattern for the organized geometry Create a 2-D Mesh Clean up the 2-D mesh TetraMesh

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The TetraMesh Process Manager will create a new tab “Process Manager” that will show the step-by-step process required to create the tet mesh.

The current step will be indicated with a white arrow with a green arrow

while completed steps will be shown

.

Additionally, the area will change from the standard HyperMesh s and will provide all the tools and functions needed to complete the current step. The standard HyperMesh s can be retrieved at any time by undocking the Process Manager s using the icon

Selecting the

.

icon will redock the Process Manager s.




Exercise 4b - Tetra Meshing Process Manager Step 1: Start the Process Manager. 1. From the Menu Bar, select Mesh > Create > TetraMesh Process >Create New to access the Process Manager.

2. Enter a session name or leave it as my_session.

Note: Creating a session name and saving the session allows the to stop the process before completion and then load it again at a later time, picking up the process at the point it was left off. 3. Select a working folder. 4. Click Create.

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Step 2: Import geometry. At this point the TetraMesh Process tab will open in the Tab area and will automatically assemble the TetraMesh Process Flow.

The first step, Geometry Import, is highlighted and the area has been configured with specific s for aiding the Tetramesh Process Manager template. You can access the HyperMesh s by undocking the Process Manager s using the icon in the upper right corner of the area. This will separate the Process Manager s so that you can also access the HyperMesh standard s. To redock the Process Manager , simply click on

in the upper right corner of the Process Manager .

1. In the area, change the Import Type to HM Model. 2. Click Import Filename: and select the file 04b-TETMESH_PM.hm 3. Click Import. The model will import and a green check will appear next to Geometry Import in the Process Manager indicating that step is now complete. 254 HMD Introduction



Step 3: Clean up the geometry. 1. From the Geometry Color Mode selector ( Shaded Geometry and Surface Edges ( ). 2. In the area, select the Edge Tools tab. 3. Click Isolate.

) pick By Topo and click

This will isolate the surfaces with free edges on them.

Isolated Surfaces with free edges.

4. Select the Free Edges tab and click Equivalence.

This will fix all the free edges. If this did not correct all of the free edges, the Tolerance value could be increased until all free edges are equivalenced. 5. Select the Edge Tools tab and click Isolate again. A window should appear with the message, “No edges found…” This confirms all edges have been fixed. 6. Click Display All. HyperWorks 13.0



7. Click ACCEPT. The Geometry Cleanup step has been completed and should have a green checkmark by it.

Step 4: Organize and Cleanup Holes. This step will allow you to organize the surfaces that form holes in the model. The TetraMesh Process Manager can automatically sort and organize holes into separate component collectors based upon their diameter. This will allow you to specify mesh type, circumference element count, and longitudinal element size for different hole groups.

1. In the area, click the + ( ) button. This will add a third line to the table. 2. On the first line, enter 3.3 into the D< field. This will organize all holes with a diameter between 0 and 3.3 units, as indicated by the Range field, into a collector. 3. Enter 5 into the second row and 10 into the third. This will allow HyperMesh to organize the holes into three collectors that will include holes ranging from 0 - 3.3 units, 3.3 - 5 units and 5 - 10 units collectively. 4. In the Num Circumference Elems field enter 12 for each row. 5. In the Longitudinal Elem Size field enter 1 for each row. The Num Circumference Elems field governs the number of elements that will be meshed around the hole while the Longitudinal Elem Size field dictates the unit size of the elements through the length of the hole.




6. Click Auto Organize. All of the holes in the model less than 10 units will now be organized into three component collectors, each with a different color.

7. Click the HyperMesh Model Browser tab and expand the folder for Components. You will see three new component collectors with the name solidholes followed by the numerical average of the diameter range of the holes organized.

Transparent view of model showing all holes and bores organized

8. Return to the TetraMesh ProcessManager tab

9. Click ACCEPT. The Organize & Cleanup Holes step is now complete should now have a green checkmark next to it.

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Step 5: Mesh holes. 1. In the area you will notice that each hole diameter row has a Mesh Type field with a pull-down providing the options of R-tria regular and R-tria union jack. that all are set for R-tria regular and click Mesh All. (The R-tria union jack mesh pattern will be discussed in a later step)

You will notice this process provides a perfectly straight tria mesh down the length of the hole with no twisting.

2. Click ACCEPT. The checkmark in the Mesh Holes step will now turn green.




Step 6: Organize and clean up features. This step allows you to highlight and organize features that require specific mesh controls beyond the overall mesh pattern that will be applied to the remainder of the part in a later step. This organizational tool will place the required surfaces into their own collector or collectors and allow you to set mesh size and pattern requirements for each. 1. In the area, click the + (

) button.

2. In the Define New window that opens, type Faces and click OK.

3. Select all five of the flat faces around the circumference of the part as shown in the following image. 4. Click proceed.

Faces that need to be picked

The will switch to the Organize with your surfaces pre-selected to move into a new component called grp_Faces. 5. Click move, then return.

6. Click the + ( ) button again. 7. In the Define New window that opens, type TopHole and click OK. HyperWorks 13.0



8. Rotate the model so you are looking at it from underneath into the center, and select the surfaces shown in the following image.

9. Click proceed. 10. In the Organize , click move, then return.

Your model should then look similar to the following image, with the faces in one collector and the top hole in another. Your colors may vary slightly.




11. Click ACCEPT.

Step 7: Organize and Cleanup Fillets. Often a better mesh can be achieved if your fillets are split down the center. The step will allow you to automatically split your fillets based on minimum and maximum radius criteria.

1. Click Components. 2. Select the part in an area that has not been organized into a new component so that the large purple part is selected. 3. Click proceed. 4. Leave the Min Radius at 0 and the Max Radius at 5 and make sure the Suppress Fillet Tangent Edges option is active. 5. Click Cleanup. You will notice that many of the fillets now have an edge running down the center and the original edges are suppressed. 6. Click ACCEPT.

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Step 8: Mesh Features. In this step you will mesh the features that you organized in Step 6. The area will show a table with your organized features in it and will give you the option of selecting a mesh type and size for each feature.

1. 2. 3. 4.

For the Faces feature, click the pull-down under Mesh Type and pick trias. For the TopHole feature, select R-tria union jack for the Mesh Type. In the field under Elem Size, enter 0.5. Click Mesh All.

5. Note the distinctive Union Jack mesh pattern ( ) in the top hole area and the connectivity of the mesh to the previously meshed holes. 6. Click ACCEPT.

Step 9: Organize & Cleanup. This step allows the to organize and clean up the remaining portion of the model that will then fall under the global meshing parameters. As the remaining surfaces are already in the component you wish them to be in, there is no need for further organization.

1. Click ACCEPT. 262 HMD Introduction



Step 10: Mesh/remesh. This step is where the remaining model will be globally meshed. Element size and type can be set for all remaining components that remain unmeshed.

1. 2. 3. 4.

In the Element Size field, enter 1. Set Mesh Type to trias. Click Mesh. Click ACCEPT.

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Step 11: Elements Cleanup. At this point the model should be entirely meshed. Proper adherence to the previous steps ensures a surface mesh that is properly connected and controlled by the previously entered values. This step will now allow the to a proper mesh and clean up any issues that are found.

1. In the area, click Components. 2. Select all of the components and click proceed. 3. Leave all of the values at their default (Min Size – 0.25, Max FeatureAngle – 60.0, Normals Angle – 150.0) and click AutoCleanup. The following message should appear.

This indicates that all failed elements have been fixed and there are no further errors in the model. 4. (Optional) The Manual tab allows the to manually check the model for free edges and t-junctions and fix any that are found. There is also the option to display normals. Use these options to find and fix any errors.

5. Click ACCEPT.




Note: The Tetramesh Process Manager will automatically place any elements that fail this AutoCleanup procedure in the mark. This will allow for easy retrieval of problem elements and the can employ the tools from the standard HyperMesh s to fix these remaining elements.

Step 12: Tetra mesh. This is the final step in the TetraMesh Process Manager Template and will be the point where the model is Tetra meshed. The Process Manager will automatically open the TetraMesh and pre-select all float and fixed elements. 1. Click elems under Float trias/quads to tetra mesh. The surface elements will be selected under the general mesh selection option. This will define them as “floatable” elements, meaning that the diagonals of the underlying tetra elements can be flipped from the generated shell elements if HyperMesh determines a better element quality will result. 2. Click elems under Fixed trias/quads to tetra mesh. The elements that represent the interior of holes and bores will be selected under this option. The will be defined as “fixed” elements meaning HyperMesh will always adhere to the shell mesh pattern with generating the tetra elements.

3. 4. 5. 6. 7.

Click mesh. Click the Model tab in the Tab area. Expand the Components list if necessary. Right-click the tetmesh component. Select Isolate Only. The tetra mesh will be displayed.

8. Click Mask (

).

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9. Hold the SHIFT key down and while holding the left mouse button down, drag a box to include roughly half of the model. 10. Click mask. Your tetra mesh should look similar to the following image.

Step 13 (Optional): Save your work. 1. You can now save your model if you wish.




3 - Solid Meshing To mesh solid geometry, the Solid Map is used.

In particular are the one volume and multi solid sub s. These allow for the automatic creation of Hexa/Penta mesh on mappable shapes.



Location: o



Mesh > Create > Solid Map Mesh

What it does: o

Creates hexa-penta mesh in 1 or more volumes 

Each volume is defined by selecting a solid geometry entity 



Easy to define shape for the mesh since only one entity is selected

Each volume must be a “mappable shape”

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Mappable Shapes To use the automatic Solid Map function the geometry must be split into mappable shapes. Mappable shapes are defined as 2 opposing faces (source and destination) and faces that directly connect the source and destination (along faces).

While this example shows two faces that are of the same shape and directly oppose each other, that is not a requirement. The source and destination can be of drastically different shape and contour and need not lie directly opposite each other. Requirements and Tips 

Shape must be a closed volume



Multiple source faces are allowed



Destination face must be a single face



No edges are permitted that are perpendicular to the drag direction. If they exist they must be suppressed.






When splitting solids into Mappable Shapes it is recommended to split the part into the fewest possible regions to save time and offer more control over the mesh size. This often means splitting parts in ways that are not perpendicular to surfaces.



Placing a 2D mesh onto a “Source” face of a mappable shape will allow control over the pattern of the resulting 3D mesh.



When splitting solids into mappable regions, shared faces will guarantee 3D element connectivity across the split. This connectivity will also assure that the mesh pattern is carried through the part as subsequent regions are meshed.

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

Mesh connectivity of properly split regions with shared faces is also guaranteed even when mesh directions of the individual regions are not the same. NOTE: The mesh pattern on the “along” faces will always be quads.




Solid Map Meshing In solid meshing, the ability to be meshed is referred to as mappability. Mappability is directional and can be likened to putting a surface mesh on one face of the solid, then extending that mesh along a vector through the solid volume.

The ability to control the mesh pattern of a solid mesh by placing a shell mesh on the surface has been available in previous versions. To achieve this, though, the had to put the shell mesh on the surface before the solid map function was performed and had to do it for each desired face. The solid map automatically places a shell mesh on the source faces and then enters into a mesh adjustment similar to the one in the automesh :

This allows for control over the mesh density and style using tools that work the same as in the automesh .

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Exercise 4c - 3D Solid Meshing with Hexas and Pentas This exercise will demonstrate a method for splitting a solid and then use the solid map function to create Hexa/Penta Solid elements. It is important to note that this is simply one way of splitting this solid. As with any solid geometry there are often many ways of obtaining a fully mappable solid and while some are better than others, there is rarely a “right” way of doing it. Experience is the key with this function; so experiment with different techniques for solid splitting and observe the results you get.

Step 1: Import the model 1. Locate and import the file 04c-STAND-SOLID-MAP.prt This model is in a ProE .prt format.

Step 2: Defeaturing Small fillets make the geometry substantially more difficult to split into mappable regions and result in a far more complex solid mesh. In many cases, these fillets are for manufacturing purposes and can be eliminated from the geometry. 1. Defeature all of the small internal surface fillets.

HINT: Setting the search values to be 0.5->5.5 will select all of the fillets needed. This range will also result in the fillet shown in the picture below to be selected (fillet in the red circle area). This fillet must be removed (mouse >Right Click) from the selected fillets, before to proceed with “remove”, as defeaturing it would cause a sharp point that would act as a severe stress concentration area.




Step 3: The first split There is no set method for splitting a solid and often the first cut is the hardest, as picking the location to begin can be confusing. Often it is easiest to find areas that look to be close to being mappable. Many regions are only one cut away from becoming mappable and these frequently are the best place to start. In the case of this model, these areas are the flat “feet”. One cut will separate them from the rest of the solid and they will immediately become mappable. 1. Turn on Mappable visualization:

2. In the solid edit select the trim with plane/surf sub.

3. Select the solid and using the N1 N2 N3 option, define a plane on the flat area as shown in the picture below.

4. Trim the solid and the result will be a mappable region on the “foot”. HyperWorks 13.0



5. Repeat this trim on the other side of the part.

Step 4: Splitting out further mappable regions. With the first splits done, now we can look to what is remaining and determine how these regions can be made mappable. It is often easiest to visualize this by masking the areas already split into mappable regions, thus showing only the areas of the part that remain to be split. 1. Mask the two mappable solids that were created in Step 3.

2. From the trim with plane/surf sub, select the solid and define a plane on the flat recessed area. 3. Trim the solid.




4. Repeat on the other side. The solid is now in three distinct regions; the two outer regions being mappable and the central region which is still un-mappable.

5. Mask the two newly created mappable solids.

Step 5: The last trims. With the thin slice of the part remaining, it is now important to determine which feature(s) is (are) causing this solid to remain non-mappable. that the rules state that a mappable solid can have multiple source faces but only ONE destination face. The surfaces that make up the face of the pocket that was on the complete solid (highlighted in white in the picture below) occur on both sides of the remaining solid. This means there are multiple surfaces on both sides of the solid and thus violate the mappable rules. In instances where specific regions prevent a solid from mapping, trimming those regions out can result in a mappable solid. HyperWorks 13.0



1. Select the trim with lines sub.

2. From the with sweep lines column, pick the remaining solid. 3. For the sweep lines, select the outline of one of the surface shown in white above.

4. As this model is aligned with the Global Axis, select the sweep to: option to be by a vector >> z-axis, select the sweep all option, and then trim the solid.




5. Repeat this process for the other side. This will result in a fully mappable solid. 6. Save the model.

Step 6: Solid Meshing With a fully mappable solid, the solid meshing tools can now be used to create the 3D elements. 1. Enter the solid map and select the multi solids sub.

2. Set the options shown below and mesh the solids. HyperWorks 13.0



The interactive multi solid meshing will allow for 2D mesh customization prior to the creation of the 3D mesh. HyperMesh will show the order in which each solid is to be meshed and will indicate the direction in which the mesh will be extruded.

Additionally the now allows the to alter the 2D mesh that will be used as the pattern to extrude the 3D elements. A similar to that used in interactive shell meshing is opened and the pattern mesh is displayed on the solids.

Using procedures identical to 2D meshing, edge densities can be adjusted, element sizes can be re calculated, mesh styles can be changed and other meshing options can be altered. Clicking the mesh button will show the solid mesh but the mesh will not be finalized until the return button is clicked so further changes can be made. 3. Use the edge density, master face style and options sub s to make changes to the mesh and see their outcome on the 3D mesh, proceed to mesh the solids. When happy with the 3D mesh, return from the function and save the part.




4 - Shrink Wrap Shrink wrap meshing is a method to create a simplified mesh of a complex model when high-precision models are not necessary. This is often the case for power train components during crash analysis. The model's size, mass, and general shape remains, but the surface features and details are simplified, which can result in faster analysis computation. You can determine the level of detail retained by determining the mesh size to use, among other options. Shrink wrap functionality was added to HyperMesh in the 9.0 release but has had its capabilities greatly expanded in the later versions. The key additions are: 

Both solids and surfaces are valid as input to the shrink wrap – it is no longer necessary to mesh the model beforehand.



Shrink Wrap meshing has been improved for loose and tight algorithms by improving the mesh flow and uniformity of the resulting mesh.



Feature recognition for tight wrap is automatic; no need to manually define features.



New “generate solid mesh” option has been introduced to provide a hexa only voxel output. A jacobian parameter is definable to control the quality of the hexa mesh.



New “mesh orientation” option is available to control the resulting shell/solid mesh which will be orientated to either the global or defined local system.

Options and Settings The Shrink Wrap function can be accessed through the pull-down menu through Mesh > Create > Shrink Wrap Mesh and the shown below will open.

Shrink wraps can be generated using two algorithms: Loose or Tight. These determine how closely the resulting mesh adheres to the details of the underlying model, and are best suited to different use cases which will vary for any given use. 

Loose Shrink Wrap - generate a loose-fitting shrink wrap mesh that generally conforms to the model.



Tight Shrink Wrap - generate a tight-fitting mesh that adheres closely to the underlying model, capturing as many features as possible.

The options for both Loose and Tight are the same and are as follows: 

Comps – Selection of the comps, elems, surfs or solids used to create the shrink wrap mesh.



element size= - Sets the desired target element size for the shrink wrap mesh.



generate solid mesh - If selected, HyperMesh creates a solid hexa mesh under the 2d shell mesh.



mesh orientation - Switch to choose element orientation with the global system or previously created local system.

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Exercise 4d - Shrink Wrap Meshing Step 1: Open the model 04d-SHRINK-WRAP-MESH.hm. Step 2: Create a loose shell shrink wrap mesh in the “loose_gap” component. 1. Click Shaded Geometry and Surface Edges if the model is not shaded yet. 2. Review the surface geometry on the screen. Notice the gap in the geometry.

3. From the pull-down menu, select Mesh > Create > Shrink Wrap Mesh. 4. Select the component in the graphics area. 5. Select the loose wrap option. 6. For element size, enter 4.

7. Click mesh to create the shrink wrap. 8. Expand the Component folder in the Model Browser. 9. Hide the surfaces component in the Model Browser. 10. Click return to exit the .




Step 3: Review the solid geometry. 1. Show the block component in the Model Browser. 2. Review the model to see the features. 3. Hide the block component in the Model Browser.

Step 4: Create a loose shell shrink wrap mesh in the loose component. 1. Hide the loose_gap component in the Model Browser. 2. Right-click the loose component and click Make Current. 3. From the menu bar select Mesh > Create > Shrink Wrap Mesh. 4. Activate the loose wrap option. 5. Click comps and select block from the component list. 6. For the element size, enter 10. 7. Click mesh to create the mesh.

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8. Click reject to reject the mesh. 9. Change the element size to 5 and click mesh to create the mesh.

10. Click reject to reject the mesh. 11. Change the element size to 3 and click mesh to create the mesh.

The shrink wrap mesh with the geometry hidden

12. Click reject to reject the mesh. 282 HMD Introduction



Step 5: Create a tight shell shrink wrap in the tight_shell component. 1. Hide the loose component using the Model Browser. 2. Right-click tight_shell and click Make Current. 3. Click comps and select the block component. 4. Activate the tight wrap option in the shrink wrap . 5. Make sure the element size is set to 3.

6. Click mesh to create the mesh.

Step 6: Create a tight solid shrink wrap in the tight_solid component 1. Hide the tight_shell component in the Model Browser. 2. Right-click the tight_solid component in the Model Browser and click Make Current. 3. Click comps and select the block component 4. Make sure the element size is set to 3. 5. Activate the generate solid mesh option. 6. Change the minimum jacobian to 1.

7. Click mesh to create the mesh. HyperWorks 13.0



8. Click reject to reject the mesh. 9. Change the minimum jacobian to 0.7. 10. Click mesh to create the shrink wrap.

11. Click

to open the Mask .

12. If not already set, set the collector to elems. 13. Use SHIFT + left mouse button to select a group of elements. 14. Click mask to mask the elements. 15. Click unmask all and return to exit the .




Step 7 (Optional): Change the minimum jacobian to 0.3 for optimized mesh. 1. Delete the elements displayed in the graphics area. 2. From the menu bar select Mesh > Create > Shrink Wrap Mesh. 3. Click comps and select the block component from the list. 4. For the minimum jacobian, enter 0.3.

5. Click mesh to generate the mesh.

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Chapter 5: 1D Meshing and Connectors

Chapter 5

1D Meshing and Connectors 1 - 1D Meshing 1D elements perform a critical function in Finite Element Analysis as they can be used to connect nodes together, attach dissimilar meshes, distribute loads and in general provide a quick and easy way to attach things together. There are numerous types of 1D elements ranging from infinitely rigid simple connections to complex cross sectioned elements that can be stressed. This chapter will cover many of the most widely used 1D elements and also cover an important tool in HyperMesh called connectors. Connectors can provide a quick and easy way to create many 1D elements with little work. •

1D Meshing

•

HyperBeam

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•

Connectors




1.1 - 1D Elements 1D mesh are simple connections between nodes, allow accurate testing of connectors (such as bolts) and similar rod-like or bar-like objects that can be modeled as a simple line for FEA purposes. You can create 1D Element from the following :

•

1D elements currently ed include bar2s, bar3s, rigid links, rbe3s, plots, rigids, rods, springs, welds, gaps and ts.

•

Plot elements are generated in the Edit Element, Line Mesh, Elem Offset, Edges, or Features .

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1.2 - HyperBeam HyperBeam Tool Properties > HyperBeam

The HyperBeam View (available in the Model Browser once the application is opened), allows you to create & control HyperBeam beam-section data in HyperMesh. HyperBeam View can be divided into the following sections: Section Browser & Parameter Definition, Graphics Window, Results and the Toolbar.




1.3 - Connectors Connectors: What are they? Connectors are a geometric representation of connections between entities. The advantage of connectors is the ability to create multiple connections at a single time. Hundreds or even thousands of connections that would normally have to be created manually one at a time can be mass created, even before the part is meshed. They can be used to create numerous types of connection elements such as:



Spot Welds



Bolts



Trim Masses



Seam Welds



Area Connections (Adhesives)

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Connectors: Terminology 



Link Entities - The entities that are being connected o

can explicitly define link entities or specify a search tolerance

o

Can be components, elements, surfaces, nodes, or tags

o

Typically components are linked

Connector Location - Where the entities are linked o

Nodes – created at the node location

o

Points – created at the point location

o

Lines – created on the line 



o

Elements – created at the element location (adhesives only)

o

Surface – created at the surface location (adhesives only)

Connector Realization – The creation of the finite element representation of that connector o





The line may be split into multiple projection locations as specified by the offset, spacing, and density values

Rigids, springs, etc., or custom configurations such as ACMs, CWELDS, etc.

Connector State – Whether an FE representation of a connector has been created o

Unrealized - The initial status of the connector entity upon creation

o

Realized - The status only if creation of the FE weld representation at the connector was successful

o

Failed – The status if creating the FE weld representation at the connector was not successful

# of Layers – number of FE weld layers to attempt to generate for the connector o

2T, 3T, etc.








Connect When – Specifies when the link entity information is added to the connector o

Now - Allows you to add link entity information now. For this option, you must select the connect what entities and num layers to successfully create a connector.

o

At FE Realize - The link entities to the connector are determined while realizing the connector. The link entities are determined by the projections and proximity from the connector location.

Re-Connect Rule – Defines method for connector re-attachment during part swapping/replacement o

None - If a link entity is deleted, the link entity is removed from the connector

o

By ID - If a link entity is deleted, the connector retains the ID of the link entity, and will to a new entity with that ID upon realization

o

By Name – Same as the by id rule except that the entity name is retained

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Connectors: Tools •

Connectors > …



Spot



Bolt



Seam



Area



Apply Mass – adds a mass value to entities o

Used to represent mass of parts that are not present in the model



FE Absorb – Create new connectors from existing elements of recognizable FE representations of welds, bolts, adhesives, etc.



Add Links – Add link entities to existing connectors



Unrealize – Delete FE representations of welds / bolts / adhesives associated with existing connectors



Compare – Checks the MCF against displayed model file



Quality – Check for duplicate connectors, combines connectors, and checks the quality of realized elements








Import Master Weld Files to automatically create connectors

Connector Browser – Hierarchal browser that provides information and the ability to edit connectors. 



Shows: o

Type of Connector

o

Link Information

o

State of connector

Editable o



Edit link entities, export mwf files, etc

Found in Tab Browser Area

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

Visualization –

Controls how connectors are displayed:



Color connectors by state, layers, or component



Visibility by state or layers (can turn the display on or off)



Control size of connector display

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Exercise 5a - 1D Meshing and Connectors This exercise will cover the basics behind the creation and visualization of 1D element, ranging from simple rigid entities to more complex 1D elements with a defined cross section to automatic 1D element creation through the use of connectors.

Step 1: Load the model 05a-1D-MESHING.hm and set the profile to OptiStruct. Step 2: RBE2 Elements RBEs (Rigid Body Elements) are the most simple of 1D elements and simply connect two or more nodes together. In the case of an RBE2, one node serves as the Independent and the other(s) the Dependent node(s). The Dependent node(s) simply “follow” the motion of the Independent node in the Degrees of Freedom that have been linked. These elements are useful to simply represent welds or to tie together two dissimilar meshes. One word of caution though is that RBE2 elements, as they rigidly link nodes together, can induce stiffness to the model that may not be desired.

1. Create a component called Rigids and make the color red. 2. Rotate the model as shown in the picture and zoom into the highlighted region. 3. Enter the mesh creation for Rigids.




4. Make sure the create sub is active. 5. Ensure that all 6 DOFs are selected.

6. Select the red circled node first (Independent Node) and the yellow circled node second (Dependent Node).

A rigid element (RBE2) will be created connecting the two nodes.

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7. Continue to make a few more RBE2 elements down the line. 8. Change the switch next to dependant node to multiple nodes.

9. Pick a node for the independent node and then pick multiple nodes for dependent. 10. Click create. An RBE2 with multiple dependant nodes connected to one single independent will be created.

11. Select the update sub-

12. Pick the RBE2 created with multiple dependant nodes. 13. Click the connectivity radio button 14. Click the nodes button next to dependent: 15. Right click one of the dependent nodes, it will become de-selected. 16. Left click a new node to select as the dependent node.




17. Click update. You will note that the connectivity of the RBE2 has changed to remove the deselected node and include the newly selected node. Update can also be used to change the independent node, the DOFs of the element and switch RBE2 independent and dependent nodes.


Step 3: RBE3 Elements RBE3 elements are useful to distribute loads without inducing unwanted stiffness. It is not an element to be used to model a connection, but rather an element to induce a motion in a node as a function of the weighted average of other nodes. 1. Go to Mesh > Create > 1D Elements > RBE3. The RBE3 will open. You will notice it looks similar to the RBE2 with the only changes being the reversal of the Independent and Dependent nodes and the addition of a weight field.

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2. Rotate and zoom so that you are looking down at the large hole in the blue upper part. In this step you will create a very common rigid element feature often called the “wagon wheel” or the “spider web”. When complete the reason will be obvious. This type of feature is used to link the nodes around the circumference of a hole to a single node in the center. This can then be used to:  Connect the feature to something else (bolting two parts together).  Constrain the central node. (Bolting to a fixture) (RBE2)  Distribute a central load. (RBE3) To create this feature, a node must be placed at the center of the hole. This can be accomplished through the use of the Distance . 3. Press F4 to enter the Distance . 4. Pick the three nodes sub . 5. Pick any three nodes around the interior of the hole. 6. Click the green circle center button. A yellow temp node will be placed at the circle center.

7. return out of the function back into the RBE3 . 8. Select the new temp node as the dependent node. 9. Pick all the nodes around the interior of the hole as the independent nodes. HINT: Using the extended selection by path option will make this task much quicker. Simply select the by path option, click any node on the circumference then click another node a ways further around. HyperMesh will automatically select all the nodes between using the shortest route. Continue in this manner until all the nodes are selected. 10. Set the weight at 1. 11. Click create. The Wagon Wheel or Spider Web will be created.




Step 4: Bar Elements – Creating the beam section RBE2 and RBE3 elements are considered “rigid” elements. They are infinitely strong and as such experience no stress and thus cannot be analyzed. In the event the 1D element is actually a structural entity that needs to be studied, a bar is used. The bar element (CBEAM in OptiStruct) has a definable cross section and material assigned to it and thus will display stress results in post processing. Before the element can be created, a cross section, a material, and a property need to be defined and then applied to the element(s). 1. From the menu bar, select Properties > HyperBeam. HyperBeam is a tool within HyperMesh that allows for easy and graphical creation of cross sections for beam elements.

2. From the HyperBeam select the standard section sub . 3. From the standard section type switch pick standard H section.

4. Click create. The graphical HyperBeam interface will now open:

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From within this interface the physical dimensions of the beam section can be defined. 5. Set the dimensions as shown below:

6. Go to the Model browser and right click on the word H_section.1, select Rename and rename it H_Beam.




7. Click File > Exit. The beam section has now been created. 8. Right click in the Model Browser window and create a property. 9. Name it H_Beam. 10. Select the property H_Beam and define its card using Entity Editor. In the Card Image ssign it a PBEAM.

11. Select Material in the Entity Editor and assign it the material Steel (select form the Material yellow button).

12. The beam section needs to be assigned to this card. Select Beam Section in the Entity Editor and assign it the Beamsection H_Beam (select form the Beamsection yellow button).

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The inertial information calculated from the cross section will automatically be placed into the value fields in the card.

Step 5: Bar Elements – Creating the bar elements With the property and cross section defined the Bar element can now be created. 1. Go to Mesh > Create > 1D Elements > Bars .

2. Click the orientation switch immediately next to the N1 button and select x-axis. 3. Click the property = button and pick the H_Beam property. 4. Pick any node on the blue upper component elements for node A. 5. With the focus automatically switching to node B, pick any node on the green lower component elements. The CBEAM element will automatically be created.




You will note that the element is displayed as a line in the color of the component it was created in. Aside from the CBEAM label, it looks identical to the RBE2 and RBE3 elements created previously. The 1D Element Representation mode allows for the graphical representation of the cross section of the 1D element. 6. Click the 1D Element Representation button ( Element Representation icon (

) and pick the 1D Detailed

).

7. Zoom on the CBEAM element. It now shows the actual cross section. This cross section is selectable and reflects the color of the component. It also is a live view so that if any aspect of the element is changed, it will show that.

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8. Re-open HyperBeam and change the dimensions to see the changes reflected on the part.

9. Create a brand new cross section of some other standard type and file > exit.

10. Right click on the H Beam property card in the HyperMesh Model Browser and card edit the property. 11. Click the beamsection button and pick the new cross section. 12. Return out of the card and see the change in the model.

Step 6: Combining 1D Elements A typical bolt representation consists of a “wagon wheel” inside the two bolt holes connected at their centers with a CBEAM that has a solid circle section that represents the bolt. In this step you will create one of those common structures. 1. Create a component called Bolts and give it a unique color. 2. Re-open HyperBeam and create a standard section as solid circle beam with a diameter of 5.




3. Create a PBEAM property named Bolt with a material of Steel and the solid circle beam section just created.

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4. Pick one of the two circle pairs between the Blue Upper Component and the Purple Flanges Component to create the bolt in.

5. Put temp nodes at the center of both the upper and lower holes 6. Create an RBE2 “wagon wheel” in each of the holes. 7. Create a CBEAM element connecting the center of the RBE2 elements with the Bolt Property. 8. Repeat this for the other hole.

Step 7: Connectors Connectors are a quick way of creating multiple and complex rigid entities representing welds, bolts and adhesives. First you will use the Connectors to create a weld of rigid elements similar to those created in Step 2, Item 6. In that case, two nodes were selected and a single RBE2 was created. To run down the entire length of the edge would have required each node be picked individually. You will now accomplish the same result using connectors in a fraction of the time. 1. From the menu bar, select Connectors > Create > Spots.




2. From the spot submenu, next to location, click the nodes button and pick by path. 3. On the opposite edge from the one used in Step 2, Item 6 to create the RBE2 elements, pick the first node and using the by path option, proceed down the entire edge until all the nodes are selected.

4. Next to connect what, make sure to select comps and pick the blue Upper Plate collector and the teal Arm collector. 5. Make sure elems is selected by the toggle and num layers should be total 2 as there are only 2 layers being connected. 6. tolerance = should be set for 10 (this determines the distance HyperMesh will search from the node to find nodes of both collectors to create the welds. The distance is a bit over 6, so 10 should work fine.) 7. For type= select rigid (this option allow you to establish what type of element will be created.) 8. Change the mesh independent switch to mesh dependent. 9. Under mesh dependent, change the switch from quad transition to remesh. 10. the has all the settings shown below:

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11. Click create. The entire row of rigid elements will be created with this one click.

The process can be used to create these types of rigids or rigids that will represent spot welds. These elements can even be created before the part is meshed (must pick geom instead of elems for the connect what option) and in that case a fixed point will be placed at either end of the element, guaranteeing that a node will be there when the mesh is created. 12. Experiment with creating other connectors in the model with other options in the . 13. From the connectors tools enter the Bolt .




14. Zoom to the section of the model shown below.

15. Pick one node on the circumference of each of the holes on the purple Flanges component, as location:. 16. Set connect what to comps and pick the purple Flanges component and the green Lower component. 17. Set the tolerance to 20 and fill in the rest of the as shown below.

18. Click on realize & hole detect details... 19. Set the values in the as the following:

20. Click return and then select create. Immediately two rigid bolts are created. If desired, the type can be set as Bolt (CBAR), and a PBAR card in combination with a beam section can be defined, and the bolt can be analyzed. Bolt (Washer) types will not only select the nodes around the circumference but will grab nodes around a washer ring as well.

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21. Experiment with other options in the .

Step 8: Connector Browser 1. From the View menu activate the Connector Browser by selecting Browsers > HyperMesh > Connector.




The Connector Browser will appear and display all of the connectors in the model. From the browser you can see information about the connectors, reasons for realization failure and when you right click on a connector you can edit the connectors. 2. Experiment with the Connector Browser.

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Chapter 6: HyperMorph

Chapter 6

HyperMorph 1 - Introduction to Morphing Technology using HyperMorph HyperMorph is a mesh morphing module in HyperMesh that allows you to morph an FE model in useful, logical, and intuitive ways which result in minimal element distortion. HyperMorph can be used to: •

Rapidly change geometry of existing model interactively or parametrically

•

Map an existing mesh onto a new geometry

•

Generate and edit shape variables for optimization

HyperMorph Highlights: •

Freehand morphing: Direct morphing of the mesh without any morphing entities

•

Morph Volumes: Efficient setup of morphing for complex FEA models

•

Section Morphing: Map to new design lines using line difference

•

Morphing Constraints: Preserve model attributes while morphing

•

Morphing Shapes: Transfer morphing between different meshes (the shape can be positioned to other parts of the model, animated to review the morphing and transfer loads from one model to another

To provide greater control as well as an efficient morphing, you can use: •

Constraints

•

Symmetries

•

Biasing factors

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After morphing has been performed, you can visualize the quality of the mesh, and can automatically smooth it if needed. A re-mesh can also be performed, keeping the morphing entities like handles, domains and shapes intact.

Accessing HyperMorph HyperMorph can be accessed in one of the following ways: •

From the menu bar, go to Morphing, and select the appropriate function:

•

On the Tool page click on HyperMorph, and click on the appropriate




HyperMorph Entities •

Handles – controls model shape during morphing

•

Domains – divides a model into regions (for domain based morphing)

•

Morph Volume – A cube shaped volume that morphs all entities that are located inside the shape (for volume based morphing)

•

Constraints – Control the motion of nodes during morphing

•

Symmetries – forces regions to be morphed symmetrically

•

Shapes – model state during morphing saved for retrieval at a later point

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2 - Free Hand Location: Morphing > Free Hand Use this to morph your mesh without needing domains, handles, or morph volumes. Separate options exist for moving selected nodes directly, recording actions made in other s, "sculpting" meshes with different virtual tools, and saving a morph as a shape. The freehand consists of several subs, changes made on one sub do not affect the others, and are persistent so that you can switch freely between subs without losing any settings already made: •

move nodes Use this to select specific nodes and move them directly to new locations while optionally morphing the surrounding mesh. Using the move nodes sub, you can translate and rotate nodes, move nodes normal to a mesh, move nodes to a vector, node list, line, plane, surface, mesh, or equation, and apply a shape. For each morphing option, you can choose whether or not the morphing should be interactive. You can also control how those node movements apply to the surrounding mesh. Note: In the morph options , morphing sub, there is an option for setting the minimum step size for interactive morphing. If the distance or angle fields are set to values other than zero the morphing will be performed in discrete steps with the given step size rather than an arbitrary value based on the position of the mouse and relative to the size of the model. For example, setting the distance to 1.0 means that interactive translation will be performed in increments of 1.0, such as 1.0, 2.0, 11.0, etc. For distance, the value is given in model units. For angle, the value is given in degrees. The minimum step size applies when using the manipulator or using translate, rotate, or move normal options.




The freehand has several types of movement:

Manipulator You may then click and drag one of the three arrows of the manipulator to translate the nodes, click and drag one of the three arcs of the manipulator to rotate the nodes about the center of the manipulator, or click and drag one of the three right angles of the manipulator to move the nodes in a plane. The images below show a triad manipulator and where to click on it to translate it along a vector, rotate it about an axis, or translate it in a plane.

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•

record Use this to turn any into a morphing . When you click start in this , the positions of all the nodes in the model are recorded. You can then go outside of the freehand and use any tool in HyperMesh to move the nodes in the model to new positions. When you return to this and click finish, those node movements will be transformed into a morph which can be undone, redone, or saved as a shape. This feature can be particularly useful when using the Quality Index to adjust a basic morph for the sake of mesh quality. For example: after morphing, go to the Record and click start, go to the Quality Index to adjust and fix any poorly-formed elements resulting from the morph, and then return to the Record and click finish.

In the below example, sculpting resulted in poorly-shaped elements (highlighted in the left image). Adjustments made in the Quality Index resolved the problems on the left side of the mesh to produce the image on the right. By recording the node movements in the Quality Index those node movements can be saved as part of a shape and can be undone.

•

sculpting Use this sub to mold a mesh with a variety of virtual tools — for example, creating hemispherical divots, cone-shaped projections, or molding sections with feature lines.

Areas of the mesh can be pushed or pulled to reshape it, creating either indentations or projections on the mesh. 322 HMD Introduction



Tool shapes include ball, cone, cylinder, node list, line, plane, surface, and mesh. Use different tools to simplify the creation of different types of deformation.

For example, use the ball along a node list or line list to create a curved channel with a rounded bottom and ends, but use the cone to create a channel with a V-shaped bottom. Similarly, the ball can create a hemispherical divot or protrusion, while the cone can create a conical pit or spike. The following images illustrate use of the "ball" tool to create a raised ridge along a node list:

Here two nodes are selected, but the tool is not yet applied.

Here, the ball tool has been applied to the mesh as if it had been rolled from one node to the other.

•

save shape Use this sub to save a current morph as a shape. This feature is a limited version of the save as shape sub located in the Shapes .

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Exercise 6a - Using Free Hand This exercise shows how to translate Nodes to Increase the Length of a Propeller Blade.

Figure 1: Original blade

Figure 2: Blade after morphing

Step 1: Load the model. Open the HyperMesh file, 06a-PROPELLER-FREE-HANDS.hm. Step 2: Morph the blade.

Method1 - Fixed Value based method. 1. Click the Morphing > Free Hand, then select the move nodes sub. 2. that the morphing method is set to translate. 3. For the translate value, key in z= -100. 4. Open the View folder in the Model Browser. 324 HMD Introduction



5. Click

next to View1 to set the view.

6. For moving nodes and fixed nodes select the nodes as displayed in Figure 3.

Figure 3: Node and element selections.

7. For affected elements select the elements between fixed nodes and moving nodes. 8. For mv bias and fx bias keep the default value (1.0)

9. Click morph to alter the blade of the propeller.

The length of the propeller blade has increased by 100. The fixed nodes do not move. The affected elements were stretched evenly to maintain element quality. The stretching of the elements takes place between the moving nodes and the fixed nodes. 10. Click undo to go back at the original shape of the propeller.

Method2 - Interactive based method, using manipulators. 11. You’re still in the move nodes sub. 12. that the morphing method is set to manipulator. 13. Leave the other parameters and options with the actual values.

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14. Select nodes (moving and fixed) and elements (affected) as you did before.

15. You should see the manipulator. If you want you can select another node as origin: as shown in the picture below to set the manipulator in a different position.

16. Zoom in and rotate close to the manipulator area.




17. Click and drag, graphically, one of the three yellow arrows of the manipulator to translate the nodes.

18. Click and drag, graphically, one of the three yellow arcs of the manipulator to rotate the nodes about the center of the manipulator, click undo.

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19. Click and drag, graphically, one of the three yellow right angles of the manipulator to move the nodes in a plane.

You may create more than one manipulator at a time by switching the toggle between single manipulator and multiple. When switched to multiple, clicking the new manip button will allow you to create a new manipulator by selecting one or more moving nodes. The different manipulators may have different selected entities and different parameters, and can be moved independently of one another. Moving a manipulator, clicking a manipulator, or simply moving the mouse over one of the manipulators will cause the to be updated to parameters for that manipulator, allowing you to change the parameters or the entities associated with them if you desire.




The manipulators can be set to be active or inactive by switching the toggle to either manip:active or manip:inactive. When active the manipulators will morph the model when moved. When inactive the manipulators will only change their own position and orientation when moved.

Summary Method1 - The length of the propeller blade has increased by 100. The fixed nodes do not move. The affected elements were stretched evenly to maintain element quality. The stretching of the elements takes place between the moving nodes and the fixed nodes.

Method2 - The length of the propeller blade has increased using interactive by clicking and dragging one of the three arrows/arcs/right angles of the manipulator to respectively translate/rotate/move the nodes. The fixed nodes do not move. The affected elements were stretched evenly to maintain element quality. The stretching of the elements takes place between the moving nodes and the fixed nodes.

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3 - Domains and Handles The domains and handles approach consists of dividing the mesh into regions called domains with associated handles.

What are domains and handles? Domains consist of selected nodes and elements. Domains and handles are divided into two basic groups, global and local. The global group consists of global domains, each of which is associated with a number of global handles. Global handles will only influence the nodes in the global domain to which they are associated. Global handles and domains are best for making large scale shape changes to the model.

The local group consists of five types of local domains: 1D domains, 2D domains, 3D domains, edge domains, and general domains. Local handles/edge domains can only influence nodes contained in the domains they are associated with. Local handles/edge domains are intended to be used to make small scale, parametric changes to the model.

While a model can contain both global and local handles and domains, it is not necessary to have both types of domains and handles in a model.




The following table describes the various domains and their symbols when they are created.

When global domain and handles are generated using autogenerate or created with the create handles option turned on, HyperMorph generates eight global handles, one at each of the eight corners of a box laid out along the global axes surrounding the model. These global handles are named “corner” followed by a number from one to eight.

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Morphing Domains & Handles Location: Morphing > Create > Domains

HyperMorph will also place at least one global handle within the box in areas of the model’s peak nodal density. These handles are named “handle,” followed by a number. Location: Morphing > Create > Domains

The automatic global handle generation works particularly well for space-frame models such as full car models. However, for small models such as a control arm or bracket, the recommendation is for you to build your own local domains and handles since you are more likely interested in changing the local area rather than the entire model. If the autogenerate process does not create handles in the positions where you want them to be, you can always delete them, reposition them, or create additional handles. Handles can be further classified as independent or dependent. An independent handle creates displacements to the model only when it is moved. A dependent handle creates displacements influenced from its own movements plus that of other handles it is linked to. A handle can be made dependent on one or more handles. This allows you to create as many layers of dependencies between your handles as you desire. For example, you can make all the handles at one cross section of a beam (modeling using 2D shell elements) dependent on a single handle allowing you to move an entire cross section while only having to select one independent handle.




What is a partition? The most important factor in local morphing is partitioning. It is logically dividing a 2D domain into smaller 2D domains, such as where the angle between elements exceeds a certain value or where the domain changes from flat to curved, is called partitioning. Proper partitioning makes morphing faster and easier. By activating partition domains can invoke partitioning when auto-generating or when creating a domain. If the is unsatisfied with the results of the partitioning he/she can change the partitioning parameters namely domains angle and curve tolerance. Figure below shows an example of partitioning. For the model on the left, the 2D domain was created without partitioning. For the model on the right, partitioning was used. Note how the 2D domains divide along angle and curvature change boundaries.

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Morphing operation - move Handles Location: Morphing > Morph The Morph consists of several subs: move handles, alter dimensions, set biasing, set constraints, save as shape, apply shapes, and morph surfaces. There are four common buttons in many of the Morph subs: undo, redo, undo all, and redo all. These buttons allow you to move forward or backward through the morphs that you have applied to your model. They remain active when you leave the but are not saved with your model unless you check the box labeled save morphs with file in the global sub of the Morph Options . Thus you could either perform an undo all before saving your model in order to return it to the unmorphed state, or check the save morphs with file box to save all of the morphs on the undo/redo list along with the file so that they can be undone when the file is reloaded. You can also clear or compress the morphs stored in the undo/redo list in the global sub of the Morph Options . Many subs of the Morph contain a button labeled options…. This button replaces the symmetry links and constraints checkboxes from earlier versions of HyperMorph. Clicking this button will take you to the Morph Options where you are able to adjust a large number of parameters that affect morphing. Location: Morphing > Morph > move handles The move handles sub allows you to move handles and morph a mesh.




Morphing operation - alter dimensions. Location: Morphing > Morph > alter dimensions The alter dimensions sub allows you to morph your mesh by selecting handles and altering the distance between them. There are many dimensional types that can be altered.

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Morphing operation - set biasing. Location: Morphing > Morph > set biasing Use this to change the biasing factors associated with each handle. You must click update to apply bias changes to the handles, unless you update them interactively.

Clicking screen edit while the bias factors are displayed will hide the edit windows. The initial bias factor for all handles is 1.000 except for dependent handles automatically generated at the ends of 1-D domains which are given a bias factor of 3.000. Higher bias values will increase the influence that handle has over nearby nodes. Lower bias values decrease the influence. Bias values of 1 give linear results that result in morphs with sharp angles at the handle locations. For exponential biasing a bias value of 2 will result in morphs with a gentle curvature through the handle locations. For sinusoidal biasing a bias value of 2.0 for a handle at one end of an edge domain and 0.5 for a handle at the other end will give a perfect circular or elliptical curve for the domain.




Morphing operation - set constraints. Location: Morphing > Morph > set constraints Similar to the Morph Constraints , this sub- allows you to fix certain nodes in place so that they do not move during a morph.

However, the functionality is limited compared to that found in the Morph Constraints . Refer to that for greater details on constraints.

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Morphing operation - Shapes. Location: Morphing > Morph > save shape The save shape sub- allows you to save the active morph as a shape entity.

Handle and Node Perturbations: You can save a shape as either handle or node perturbations. The difference becomes important when the model is reparameterized or when domains, handles, and symmetries are created or deleted. When a shape is saved as node perturbations, it always has the same shape no matter what changes occur with the morphing entities. If the shape is saved as handle perturbations, changes in the relationships between handles and nodes will alter the resultant node perturbations when the shape is reapplied. Location: Morphing > Morph > apply shapes The apply shapes sub- allows you to saved shapes to the current mesh. This feature is a limited version of the apply shapes sub- located in the shapes .




Optimization using HyperMorph Shapes in HyperStudy You can perform an Optimzation in HyperStudy with one of the following methods: 1. You can start HyperStudy from the Application pull down menu

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2. You can export these HyperMorph Shapes to be used in HyperStudy as parametrized file model.

Note: a. HyperMesh – HyperStudy connection is not limited to shape variables, other properties such as thicknesses, loads can also be imported from a HyperMesh model to a HyperStudy session. b. Please refer to HyperStudy Online Help to get more details.




Morphing operation – Morph Surfaces Location: Morphing > Morph > morph surfaces Use this to Morph the surfaces in the model to adhere to any morphing of mesh nodes that were previously associated with them.

Surface morphing will only morph surfaces that have nodes associated with them and whose associated nodes have been morphed. There are several ways that result in a node being associated with a surface. When you automesh a surface, the nodes for the elements are automatically associated with the surface. Also, you can use the node edit to associate nodes to surfaces. Note that after morphing nodes, the morphed nodes will no longer be associated with their surfaces, but HyperMorph will save (and accumulate) the associations so that the surfaces can be morphed at a later time. There are no inputs on this sub; all surfaces are morphed when you click morph surfaces. If the results are unsatisfactory, you may reject them.

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Morphing operation – Symmetries Location: Morphing > Create > Symmetries The Symmetry allows you to create symmetries that influence handles, morph volumes, domains, blocks, rwalls, and shapes.




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Exercise 6b - Using Domains and Handles In this exercise you will create domains, handles and morph the model.

Step 1: Load and review the model. Open and review the HyperMesh model 06b-DOMAINS-HANDLES.hm.

Step 2: Auto generate 2-D domains and handles. 1. Click the Morphing menu in the menu bar and pick Create > Domains. 2. Change the create method to auto functions.

3. Click generate. Based on the model’s geometric features, all of the model’s elements are organized into various domains and local handles are created and associated with the domains.




Step 3: Move elements into a new 2-D domain. 1. Set the selector for methods to 2D domains. Toggle to the elems selector if not already there. 2. Click

to clear the elements that were already selected.

3. Using elems >> by window, select the elements indicated in figure 1.

Figure 1: Elements to select to move into a new domain

5. that partition 2D domains is active.

6. Click create to create the domain. Local handles are created for the new domain. You should now have two local domains. Elements can only belong to one domain at a time. Thus, the elements you selected were moved into the new domain. This functionality makes it very easy to group elements into different domains.

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Step 4: Split the edge domain of the radius to have more control when morphing. 1. Click the edit edges sub in the Morphing > Domains . 2. that the split option is selected. 3. With the domain selector active, select the edge domain of the part’s radius as indicated in the Figure 2. The node selector automatically becomes active once the edge domain is selected. Click the domain selector to make it active and see that you selected the desired edge domain.

Figure 2: Edge domain to select




4. Click the node selector to make it active. 5. Select the node on the positive Y-axis end of the radius, as indicated in the Figure 3.

Figure 3: Node selection to split the edge domain of the radius

6. Click split to split the edge domain at the node. 7. Repeat the above process to further split the edge domain of the radius, this time at the node indicated in the Figure 4.

Figure 4: Node selection to further split the edge domain of the radius

8. When complete, click return to exit the .

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Step 5: Add local handles to the 2-D domain on the part’s left side. 1. Click the Morphing menu, and pick Create > Handles. 2. For name=, enter local. 3. Click the attached to: domain selector to make it active. 4. Select the 2-D domain on the part’s left side by selecting its red icon, as indicated in the following image.

Figure 5: Adding handles to a 2-D domain

5. Click the by nodes: nodes selector to make it active. 6. Select the two nodes as indicated in the previous image. 7. Click create to create the handles and add them to the 2-D domain.





Step 6: Perform basic morphing to understand how domains and handles interact with each other and the mesh. 1. Click the Morphing menu, and pick Morph. 2. Select the move handles sub if not already there. 3. Change the mode to interactive if not already set. 4. Switch from manipulators to on plane. 5. Click the N1 selector to make it active. 6. For N1, N2, and N3, select any three nodes on the model to define a plane. 7. With the handles selector active, select the two handles on the right-hand end of the part, as indicated in figure 6, marked by the red circle.

Figure 6: Example result of morphing the model

If you select one or more handle, those handles follow the handle you drag. 8. Click morph. The message, “pick handles and move to new location” appears in the status bar. 9. Click on and drag one of the selected handles to morph the part. As you drag the handle, the mesh’s size and shape is adjusted.

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Notice that the following occurs as the selected local handle is moved: •

The handles selected in step 6.7 above follow the handle you are dragging.

•

All of the elements belonging to the selected local handle’s 2-D domain are affected by moving that local handle.

•

The 2-D domain’s non-selected local handles act like anchors (they do not move).

•

The nodes on the edge domains and between any two non-selected local domains do not move.

•

None of the elements in the other 2-D domain are affected.

10. Click undo. The HyperMorph module allows for multiple levels of undo and redo for all morphing operations. This functionality is available for any particular HyperMesh session and its current model as long as the session and its model remain open. 11. Click

to clear the selected handles.

12. With the handles selector active, select one or more global handles.

13. Click morph.




14. Click on and drag any global handle to morph the part.

Summary The following occurs as the selected global handle is moved: • • •

The handles selected in Step 6.7 above follow the handle you are dragging. The non-selected global handles act like anchors (they do not move). All of the elements, local handles and edge domains are affected.

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4 - Morph Volumes Location: Morphing > Create > Morph Volumes The Morph Volume allows you to create, edit, save, load, convert, and delete morph volumes.

A morph volume (or "mvol") is a six-sided prism that can be used to manipulate a mesh by manipulating the shape of the morph volume, while maintaining tangency. Morph volumes are very malleable; the length and curvature of each edge can be modified independently of the others, and adjacent morph volumes can be linked through various tangency conditions. This malleability allows you to enclose a given mesh with morph volumes, alter the morph volumes to fit your model, and then change the shape of your model by modifying the morph volumes. Morph volumes present a simple, powerful, and intuitive way to morph.

Matrix: a morph volume with handles at the corners.

Drag: volumes dragged along a node list




Hexa convert: volumes spun about an axis

Drag: profile lines dragged along a line to create morph volumes.

This rectangular matrix has X, Y, Z density of 3,3,3

This cylindrical matrix has X, Y, Z density of 2, 8, 1

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The length and curvature of each edge of a morph volume can be modified independently.

Adjacent morph volumes can be linked through tangency conditions. This allows you to update the characteristics of the morph volumes. Handles are placed at each of the vertices of the morph volumes. Morphing involves moving these handles. Morph volumes thus present a very simple, powerful, and intuitive way to morph.

Morph volumes will only morph the mesh for nodes that have been ed. In some cases, nodes within morph volumes are automatically ed when the morph volumes are created, while in others only the selected nodes or nodes on selected elements are ed. If the morph volumes do not appear to be morphing nodes inside them, you may need to those nodes. (See the update mvols sub for more details.) Although morph volumes can be created, edited, and deleted in this , the actual morphing of morph volumes is performed either in the Morph , where you can move the handles, or the map to geom , where you can map morph volume edges to a variety of entities. Morph volumes behave very much like domains (by moving the handles associated with the morph volumes the enclosed mesh can be manipulated) but morph volumes have the additional feature that you can morph them independently of the enclosed mesh. For instance, if you wish to change the shape of your morph volumes without affecting the mesh you can set the morph volumes to be inactive. This allows you to use all of the morphing capabilities to modify the shape and position of your morph volumes to better fit your mesh. Then you can switch the morph volumes back to being active and use them to morph the mesh. Note that when you set your morph volumes back to being active, you may be asked whether you want to remove the inactive handle perturbations from the morph list. Clicking yes, which is recommended, will make it so that the undo and redo buttons do not undo and redo the inactive movements of your morph volumes. Clicking no will treat the morph volume perturbations just like any other morphing. The toggle that allows you to switch 354 HMD Introduction



morph volumes between being active and inactive can be found in the parameters sub of the Morph Volumes , and in the morphing sub of the Morph Options . (See the parameters sub for more details.)

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Exercise 6c - Using Morph Volumes This exercise shows how to change the Shape of the B-pillar with the help of Morph Volume

Figure 1: B-Pillar before and after morphing

Step 1: Load and review the model. Open the HyperMesh file, 06c-MORPH-VOLUMES.hm.

Step 2: Create morph volumes. 1. Click the Morphing menu in the menu bar and pick Create > Morph Volumes 2. Switch the creation method to pick on screen. 3. For handle placement, select corners only. 4. Keep the auto-tangent check box selected.

5. Click the XZ Right Plane View (

) icon to set the view.

6. Draw a window by clicking at the four places shown in Figure 2.




Figure 2: Points for creating the morph volume

Note:

A morph volume is created, enclosing the area.

Step 3: Split the morph volumes. 1. Click the split/combine sub in the Morphing . 2. the split toggle is set to split mvols: by edges

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3. Select an edge of the morph volume close to location 1 (Figure 3).

Figure 3: Locations to split the morph volume

The green colored cross moves to the location of the black dot.

4. Click split. The morph volume is split into two.




Follow the same steps to create another split at location2 (see Figure3).

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Step 4: Change the profile of the b-pillar. Method1 - Fixed Value based method. 1. Click the Morphing menu and pick Morph. Click the move handles sub if not already open. 2. Set the morphing method to translate. 3. Set direction as along xyz. 4. Fill in the following values: x val = 0 y val = 100.00 z val = 0

5. Select the eight handles by window as shown in Figure 4.

Figure 4: Select handles for morphing

6. Click morph. Rotate the model to observe that the b-pillar is morphed.




7. Click undo to go back at the original shape of the b-pillar.

Method2 - Interactive based method, using manipulators. 8. You’re still in the move nodes sub. 9. that the morphing method is set to interactive and manipulators. 10. Leave the other parameters and options with the actual values.

11. Click the XZ Right Plane View (

) icon to set the view.

12. Select the eight handles by window as shown in Figure 5.

Figure 5: Select handles for morphing HyperWorks 13.0



13. You should see the manipulator. If you want you can select another node as origin: to set the manipulator in a different position.

14. Zoom in and rotate close to the manipulator area.

15. Click and drag, graphically, one of the three yellow arrows of the manipulator to translate the nodes, click undo.

16. Click and drag, graphically, one of the three yellow arcs of the manipulator to rotate the nodes about the center of the manipulator, click undo.




17. Click and drag, graphically, one of the three yellow right angles of the manipulator to move the nodes in a plane, click undo.

You may create more than one manipulator at a time by switching the toggle between single manipulator and multiple. When switched to multiple, clicking the new manip button will allow you to create a new manipulator by selecting one or more moving nodes. The different manipulators may have different selected entities and different parameters, and can be moved independently of one another. Moving a manipulator, clicking a manipulator, or simply moving the mouse over one of the manipulators will cause the to be updated to parameters for that manipulator, allowing you to change the parameters or the entities associated with them if you desire. The manipulators can be set to be active or inactive by switching the toggle to either manip:active or manip:inactive. When active the manipulators will morph the model when moved. When inactive the manipulators will only change their own position and orientation when moved.

Summary The b-pillar is morphed in a smooth fashion with minimum distortion to the elements in both methods.

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5 - Map to Geometry Location: Morphing > Map to Geometry The Map to geom does not include any subs, but its layout changes dynamically depending on the options chosen, beginning with the type of geometry you wish to map to.

You can complete inputs in any order, but since the layout can alter depending on the inputs chosen, it is best to work from left to right to avoid negating any settings you've already made if an "earlier" input setting changes the options for inputs you have already selected. Some of the types of geometry that can be mapped are shown below:

The following is an example of Map to Geom. The marked nodes and line are selected in the picture on the left and the fit to line option chosen. The picture on the right shows the results of clicking the automap button. HyperMesh distributes the selected nodes along the specified line, and the rest of the mesh stretches to accommodate the mapping.




In the following example the highlighted morph volume edges are mapped to the line while the dimmed edges are selected as follower edges. The highlighted edges are mapped directly to the line while the follower edges are given a similar morphing. Note that the number of handles per edge was increased to three to improve the accuracy of the mapping.

The Control can also be used to place handles and edge domains before the previously selected mapping operation takes place. This capability is useful when mapping a mesh to a surface. After selecting the mesh and surface you can go to the Control and fit each edge of the mesh to the lines around the surface. Then when you map, the mesh will be fit to the surface.

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Exercise 6d - Using Map to Geometry In this exercise, you will use the line difference approach to change the Curvature of a Bumper to a Curved Line

Figure 1: Bumper before and after morphing

Step 1: Load and review the model. Open the HyperMesh file 06d-MAP-TO-GEOM.hm.

Step 2: Morph the bumper. 1. Click Morphing > Map to Geometry to open the Map to Geom 2. Change the geometry selector to line difference. 3. Select from line: and to line: as shown in figure 2.

Figure 2: from line and to line




4. Toggle the morphing entity (2nd column) from map domains to map nodes. 5. Select nodes >> displayed. 6. Use no fixed nodes (2nd column, 2nd row). 7. Use map by line axis morphing with a value of 1.0 for mvbias and fxbias (column 3).

8. Click map.

Summary The profile of the bumper is changed to follow the new section line.

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Chapter 7: Analysis Setup

Chapter 7

Analysis Setup Analysis setup is the definition of all information for an analysis besides the mesh including: 

Specification of the solver to be used



Creation of materials, properties, etc.



Assignment of a solver specific format to HyperMesh entities



Creation of boundary conditions (constraints, loads, s, etc.)



Definition of other required information (solution requests, general run parameters, etc.)

1 - General Analysis Setup Process & Tools General Setup Process •

Importing Geometry

•

Creating Collectors

•

Create & Edit Geometry Data •

Obtain line and surface geometry from an external file, or hand digitize the data

•

Reconcile conflicts in the geometry and prepare it for use

• Create & Edit FE Model •

Build the model by using element-building s

•

Create Properties & Materials

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•

the Quality of the Model

•

Create Boundary Conditions, Load Steps and Control Cards •

Create Boundary Conditions (Loads and Constraints)

•

Create Load Steps

•

Define Control Cards

•

Run Analysis with Solver (OptiStruct)

•

Result Visualization

General Setup Process Tools 1) Load the appropriate template for that solver 

Preferences > Profiles OR




2) Create the entities needed for your model 

Collectors pull-down menu



Collectors toolbar OR



Model browser + Entity Editor

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

Entity Editor  Solver Specific Data 

You can create and edit this data using the Entity Editor.



Card Image: you can change the Card Image assigned to an entity using the Entity Editor. Edit an entities ID and Name: To change the Card Image, click the Value field and then select a new Card Image from the drop-down menu. The Card Images available in the drop-down will depend on the profile and the entity type.






Property & Material: Element property and material assignment rules are based on the profile. You can modify the entity selection in the Entity Editor by asg another entity or entities from the Selection List dialog or from the Entity Selector.

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3) Load the proper card image or type where needed. 

Collectors pull-down menu



Set a “current element / load type” for an element / load configuration 

Any new elements / loads of that configuration created will have that element / load type



Change the element / load type of existing elements / loads



Generally use the elem types or load types



Elements and loads will always have a type and configuration



Sometimes collectors may not need a card image



Entities Configuration and Types:

4) Enter values in the card images as required 

Card Image > Use Model browser + Entity Editor to edit a collector: 

Model Browser  select a collector



Go to Entity Editor and View/Edit the card image of the selected collector.






Card Image > Collectors toolbar > Card Edit of all collectors.



Preferences > Graphics pulldown menu 

to check card images

template labels (type)

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

Solver Browser 

The Solver Browser provides a solver perspective view of the model structure in flat, listed tree structure. Hierarchical structures are only available for card images that allow variations with themselves.



Displays solver-based cards in a tree format



Uses organization & structure of the represented solver



Performs basic actions involving cards





Create new cards



Delete existing cards



Edit attributes of existing cards

Display controlled in the menu bar: View > Browsers > HyperMesh > Solver






The Solver Browser includes toolbars, a context-sensitive menu, and controls built into the display tree.

5) Enter values in the card images as required Create Boundary Conditions, Load Steps and Control Cards 

Load Collectors 

The final step in the model building process is to apply constraints and forces and to create or assign coordinate systems. Before you apply loads, you need to create a Load Collector.



Loads are displayed in the color assigned to the load collector. The size of loads and constraints is based on model units and can be modified from within the boundary condition s.



HyperMesh stores and displays all loads in the global coordinate system and, if needed, it transforms the loads appropriately to any local nodal output coordinate system.



Load collectors collect and organize loads. Load Collectors are created, edited, and deleted from one of the following Tools:



Model Browser  select a collector

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

Model Browser + Entity Editor  they are shown under the Load Collector folder.



From the pull down menu Collectors > Create > Load Collectors or



Loads and equations can be organized into a load collector using the Organize



New loads and equations are automatically






Load Collectors – BCs Types 

Boundary Conditions define limits as well as loads on geometry and mesh.



Load entities have associated load configurations.



BCs Entity can be created from one of the following Tools:



FE Loading





Loads (constraint, force, pressure, moment, temperature, flux, velocity, acceleration)



Equations (mathematical link between nodes)

s 

Group (defines between entities)



Surfs (defines a list of entities that can be used as master or slave in a group).

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

Load Collectors – BCs > Load on Geometry 

Loads can be created on geometry as well as FE entities



The Loads on Geometry allows you to map loads or boundary conditions from geometry entities (loads on geometry) to the associated FE mesh entities (loads on mesh). More than one mesh can be associated with the geometry entity to which the loads are applied. The loads are mapped to all the meshes associated with the geometry entities to which they are applied.



The loadcols selection box lists a group of load collectors that contain the loads on geometry to be mapped.



Once a load collector is selected, click map loads to perform the mapping.






Load Steps – Setup > Create > Load Steps

OR Load Steps – Tools > Load Steps Browser



The Load Steps allows you to create and update collections of load collectors, groups, and output blocks.



Not all options will apply to each profile.

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

The Load Steps allows you to select and combine Load Collectors previously defined that contain Loads and Constraints entities.



The current load step displays in the name = field in the upper left.



Multiple Load Steps are allowed in the same analysis.



Load Steps Card Images






Control Cards – Setup > Create > Control Cards



Control cards allow you to add input and output parameters to a model, including location and names of the input, output and scratch files; the type of run (analysis, check or restart); overall running of the analysis or optimization; and type, format and frequency of the output.



Control cards are assigned to your model from within the Control Cards . This lists all of the control cards defined for the solver/ profile that you currently have loaded; you can disable, enable, or delete cards as desired.



Control Cards > Card Images (OptiStruct Profile):

6) Model Summary 

Tools > Summary Template 

The Summary Template allows you to obtain a summary of component element counts or element properties of the current model. You can define your own summary by creating a template file.



Displays a text window with various types of information about the model



Helps to review the model and make sure all information has been entered properly

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7) Run Analysis with Solver (OptiStruct) 

Optimization > OptiStruct



To run the analysis click on OptiStruct




8) Result Visualization in HyperView 

HyperWorks Solver View > Results 

You can view a different input/result file clicking on View



Click on Results to open Hyperview and load h3d file by default (model+results); click on Apply.

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

In HyperView you can review results using Contour



Deform

, animate

,

and many others.




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2 - Part Replacement Tool 

The Part Replacement dialog enables you to replace elements in an existing component/part with new elements. It also restores the referenced items in the original model to the new part, for example 1-D connections, masses, equations, boundary conditions, and loads. A message log is provided, which lists the entities being replaced and reconnected as well as cases that require or will require interaction.



The Part Replacement dialog generates a log file that contains a list of the entities being replaced and reconnected in addition to cases that require interaction.





Full component replacement



All references



New component: model or external file



Result preview and checks



Update loads, boundary conditions, connections, s, etc.

View > Browsers > HyperMesh > Utility tab > Part Replacement






Preferences > Profiles OR that solver



Utility tab > Part Replacement

, Loads the appropriate template for

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Exercise 7a - Analysis Setup and Loading This exercise will focus on setting up a model for analysis. At the end of this exercise, you will run an analysis in OptiStruct. While this exercise is focused on an OptiStruct Analysis setup, the methods and techniques explored here are applicable to a setup in any solver.

Step 1: Load the file 07a-ANALYSIS-SETUP-OPTISTRUCT.hm and the OptiStruct profile.

Step 2: Studying the Model The normal process for setting up an analysis would be the setup of materials, properties and components before the meshing of the model. As this exercise focuses only on analysis setup, the mesh has already been created for you. This model is a quarter segment of a submarine pressure hull. The exercise will cover the steps required to analyze the stress on the hull of a decent to a depth of 300 meters and determine if the hull design can handle that pressure. 1. Take a few minutes to familiarize yourself with the model and get a concept of the size and scale of the parts. 2. Based upon measurements and knowledge of how large a submarine is, what would you assume to units of this model to be? Now that the scale of the model has been determined, it is important to establish a unit scheme. These are often dictated by corporate standards, but in this case it will be established by the units that were used to create the model. For this analysis, the Millimeter-Ton-Second scheme will be utilized. 390 HMD Introduction



The first step in any analysis should be model organization. This frequently occurs before the model is meshed but can be done post mesh as well. To make sure each step has the information already available, the ideal order is to create materials first, then properties and then finally component collectors.

Step 3: Model Organization In this step we will take the elements that represent the Hull and place them into the Hull component. The collector that holds the remaining Rib elements will then be renamed Ribs.

Component collectors are, as previously discussed, used for model organization. One of the most logical organization schemes for this model would be a component for the Hull elements and then another for the Ribs. This, of course, is only one method and could be altered for any number of organizational reasons. 1. Right click in the Model Browser and select Create > Component

2. A new component will be created and you can edit it using Entity Editor. Enter Hull in the Name: field. Assign it a unique color.

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3. Organize (

) the Hull elements into the Hull component.

HINT: Using the extended selection option of By Geom and picking the 20 surfaces that make up the hull is the easiest way to get all of the appropriate elements.




4. Rename the Middle Surface component to Ribs.

Step 3: Material and Property Creation. 1.

Right click in the Model Browser and select Create > Material.

2. A new material will be created and you can edit it using Entity Editor. Enter Steel in the Name: field. 3. Pick a color. 4. For Card Image select MAT1 (A Linear Elastic Isotropic Material) 5. Click [E], [NU] and [RHO] to open the fields. These fields are the material properties for the material being created and are defined as follows:   

[E] Young’s Modulus (Modulus of Elasticity) [NU] Poisson’s Ratio [RHO] Density

As it has been established the Millimeter-Ton-Second unit scheme will be utilized, the Young’s Modulus needs to be in of Newton/mm2 (MPa) and the Density in Ton/mm3. Poisson’s ratio is unit-less and is the same no matter what the unit scheme.

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Enter the following values:  [E] 2.4e+5 

[NU] 0.3



[RHO] 7.85e-9

At this point you can see that a new field has been created in the Model Browser, Material, and the new material, Steel, is included in it. 6. Right click in the Model Browser and select Create > Property. While the elements (quads and trias) have been created, they need to be defined as an entity the solver can analyze. In the case of OptiStruct, these 2D elements are defined as PSHELL. Creating the PSHELL property will give these elements their definition (card Image) and will allow for the definition of the material thickness they have. 7. A new property will be created and you can edit it using Entity Editor. Enter Hull in the Name: field. 8. Pick a color. 9. For Card image select PSHELL. 10. Set the value for Thickness [T] field at 19. 11. Go to the Material field; “Select from list” the material “Steel”, to assign this material to the property.




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12. Right click in the Model Browser and select Create > Property. 13. Using the techniques explored, create a property with the name Ribs with the following settings: Card image = PSHELL Material = Steel Thickness = 13 Set a color.

Step 4: Property and Material Assignment. Property and material can be created without creating a component at the same time. This is usefull when the components already exists, you can assign property and material later. As the component were created prior to the creation of the properties, it is now necessary to assign the property to them. 1. From the Model Browser, select component “Ribs”. 2. The Entity Editor will open, Go to the Property field; “Select from list” the property “Ribs”, to assign this property (and associated material “Steel”) to the “Ribs” component.




3. From the Model Browser, select component “Hull”. 4. The Entity Editor will open, Go to the Property field; “Select from list” the property “Hull”, to assign this property (and associated material “Steel”) to the “Hull” component.

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Step 5: Load Collector Creation 1. From the Model Browser, create a LoadCollector. 2. The Entity Editor will open, Name it Pressure. 3. Assign it a unique color 4. Leave the Card image as none 5. Create the load collector.

6. Follow the previous steps to create another LoadCollector called Constraints. 398 HMD Introduction



Step 6: Model Loading With the elements properly assigned a card image (through the property) and a material, it is now necessary to create the loads on the model. As this is a submarine hull, a constant pressure will be applied to the exterior of the hull, directed inwards normal to the elements. To establish the orientation of the pressure load, the element normals direction must first be discovered. 1. Go to View > Toolbars > HyperMesh > Checks toolbar, select the Normals icon

.

2. In the elements sub- select all of the elements in the Hull collector.

3. Click display normals. Arrows should now indicate the element normal direction.

HyperWorks 13.0



The element normals should be pointing outward from the hull, so if they are not, click reverse normals. 4. Make the Pressure Load Collector current. 5. From the BCs pull-down, proceed to the Create > Pressures . 6. In the create sub-, select the elements in the Hull collector. 7. Set the magnitude = to -3.0. (This value is in MPa and corresponds to the approximate pressure at a depth of 300 meters) The direction switch under the magnitude field allows for the direction of the pressure to be set. If this value is NOT set then the default is to make the pressure normal to the element. The value previously entered was negative so that the pressure is opposite the element normal and thus directed inwards. 8. Change the magnitude%= toggle to uniform size = and set it to 200. This option establishes the size of the arrow that will graphically represent the load. Magnitude% will make the arrow length the set percentage of the value of the load in model units. For example in our case of a 3.0 magnitude load, a magnitude%= value of 200 would result in a load arrow of 6 units in length. Uniform size will set the length to the set number of model units regardless of the magnitude value. 9. Click the load types= button and select PLOAD.

PLOAD is the standard pressure loading card in OptiStruct Analysis. For explanations of other types of pressures and loads you can refer to the online help. 10. Create the pressures. The model should now look similar to this picture. 400 HMD Introduction



Step 7: Save the Model While this step is optional, it is good practice to frequently save your model.

Step 8: Constraints Constraints hold the model in place. Without them any force applied to the model would send it flying off. Constraints typically represent the physical restrictions on a part, some examples being welds, fasteners or other parts that constrain the part and allow it to resist the forces applied. These are represented through the use of an SPC (single point constraint) which restricts the movement of a single node in any of 6 degrees of freedom (X,Y Z translational and X,Y,Z rotational) In the case of this model, a special constraining system called Symmetric Constraining is used. This is a common practice when analyzing a part with some form of symmetry. In the case of this Submarine Hull model, it represents ¼ of the complete hull circle. Analyzing only part of a symmetric model saves time in both model setup and analysis. The results can be assumed to be identical across planes of symmetry, assuming the loading is also identical across the plane. 1. From the Model Browser, select Load Collector “Pressure” and right click on “Hide” 2. Make current the Constraints load collector. 3. From the BCs pull down, proceed to the Create > Constraints. HyperWorks 13.0



4. Select the YZ Front Plane View

.

5. Select or de-select the appropriate check boxes so that the only DOFs selected are 2, 4 and 6.

6. Using a box select (HINT: Shift-Left Mouse Drag a box) to pick the nodes shown in the image below.

7. Click create. 8. Select and de-select the appropriate check boxes so that the only DOFs selected are 3, 4 and 5.

9. Using a box select pick the nodes shown in the image below.




10. Click create. 11. Select the XY Top Plane View

.

12. Select and de-select the appropriate check boxes so that the only DOFs selected are 1, 5 and 6.

13. Using the standard views and model rotation tools, select all of the nodes on both remaining edges of the Hull elements. You will have to manually select the nodes at the end of the ribs, component “Ribs”, zoom and rotate the model.

14. Click create. HyperWorks 13.0



15. The model is now properly constrained for the analysis.

Step 9: Define the LoadStep This step in the analysis setup is to establish a load step. A load step is combination of constraints and loads that will define a single analysis in the solver. Multiple load steps can be defined in a single model allowing for one run of the solver to conduct numerous studies. 1. From the Model Browser, create a LoadCollector. 2. The Entity Editor will open, name it as “pressure load”. 3. Go to the SPC field; “Select from list” the Loadcol “Constraints”.

4. Go to the LOAD field; “Select from list” the Loadcol “Pressure”.

5. Go to the ANALYSIS field; select the checkbox and set analysis TYPE as “Statics” from the menu.

6. The Load Step “pressure load” is defined.




Step 10: Control Cards Control cards are special cards in the deck that control aspects of the solver run. They can be used to: 

Set parameters of the analysis.



Control aspects of the analysis.



Request certain types of output.

1. From the Setup pull-down, proceed to the Create > Control Cards . 2. Find the FORMAT card ans click on it. (Use the next button move scroll through the cards). 3. Change the number_of_formats field to 2. 4. Change the second FORMAT card to HM. This will provide output in both HyperView (H3D) and HyperMesh (HM) formats.

HyperWorks 13.0



5. Click return and then use next to find the SCREEN card. 6. Set the SCREEN_V1 to OUT

7. From the Model Browser, have a look at the cards created.




Step 11: Run the Analysis For any other solver the next step should be to export a solver deck and use the individual solver tools to being the study. As OptiStruct is an Altair product it can very easily be invoked from within HyperMesh. 1. From the Optimization pull-down, select OptiStruct . 2. Set the options to match those below. NOTE: Your model name and path will differ from the picture, leave the default.

3. After the settings are made, click the OptiStruct button to begin the analysis. 4. A new window will open to show that the OptiStruct analysis is running. 5. When the message “ANALYSIS COMPLETED” appears, the run is complete and the window can be closed.

HyperWorks 13.0



Step 12: Post Process While the workings of HyperView will be discussed in greater length in the Post Processing section of the class, this step will cover basic post processing steps to review the analysis you just ran. 1. In the HyperWorks Solver View dialog box, click the Results button to load the results in HyperView

.

2. If you want, you can load a different input/result file clicking on Load model (load .fem as input file) and Load results (load .res as result file); leave h3d format for now and click on Apply.

3. Enter the Deformed . 4. Set the Value to 100 and click Apply.




5. Change the animation type to Set Linear Animation Mode.

HyperWorks 13.0



6. Go to the Contour

.

7. Select the Result Type to be Element Stress 2D&3D (t). 8. Change Averaging Method to Advanced. 9. Set Display > Interpolate Color. 10. Click Apply.

11. Click the animate icon

.

12. Rotate the model to review it using the same keys and buttons as HyperMesh.

Step14: Engineering Review 1. Given that the Yield Strength of an HSLA Steel is around 360 MPa, do you think this structure, as designed, will survive a dive to a depth of 300 meters? 2. Using the Card Editing functions, experiment with thickness values to determine how the changes affect the stress and deformation of the model and achieve a model that does not exceed the yield strength. NOTE: The more weight of the structure, the less weight that can go in it so try to keep the materials as thin as possible. 410 HMD Introduction


Chapter 8: Capstone Project

Chapter 8

Capstone Project 1 - Bringing it all together. At this point all of the major topics have been discussed, demonstrated and tried. Now it is time to put them all together and experience a project on the full process that the engineer will experience using HyperMesh in a real world situation. This final exercise will cover the following topics: 

Importing a Model



Geometry Cleanup



1D Meshing



2D Meshing



3D Meshing



Analysis Setup



Model Loading



Analysis



Post Processing

Each of these topics has been covered in previous chapters and the student is encouraged to use this manual as a reference guide to assist in performing these tasks.

HyperWorks 13.0



Exercise 8a - Capstone Project This is a pseudo realistic situation where you as an analyst will be asked to determine the inertial effects of a thrust scenario on a satellite in orbit. This will be an idealized analysis as satellites typically do not have thrusters of this sort and in that we will be assuming many things. We will also be ignoring other external factors such as micro gravity.

Step 1: Loading the model and setting the Profile 1. Import the IGES model Solars.igs. In most cases you will be asked to start your analysis from a CAD model. This is a geometric representation of the solar s that will be attached to the satellite that we need to study. 2. Import the HyperMesh Model SatelliteBody.hm. There are often times when you or a coworker will have a HyperMesh model of a part that needs to be included in your model. In this case we can import a HyperMesh model into our current session.

3. Save the model. Name the model whatever you wish but be aware of the location the model is being saved. It will be the working directory unless that has been changed during the session of HyperMesh. 4. Load the OptiStruct Profile.

Step 2: Clean up the geometry 1. There are some issues with the model that need to be fixed to assure an accurate representation of the geometry. Find and fix them. HINT: Do not use the AutoCleanup tool on this model. to use visualization tools. There are 4 areas that need to be fixed (Component “Body”). 2. Eliminate the solar mounting holes on the satellite body. Holes can have an especially detrimental effect on the quality of mesh and if they are not needed, it is best to remove them. 412 HMD Introduction



HINT: The holes locations are important as we will be attaching the solar s at their location after we mesh. Make sure there is a fixed point at each hole location so a node will be placed there in the mesh.

Step 3: Organize the model 1. Move the Solar surfaces to a component called Solars (Choose any color you wish). 2. The component Electrnics is misspelled. Correct the spelling of the component name to Electronics. 3. Green is often a poor choice for a component color as it can hide topological colors of shared edges. Change the color of the Engine component to Grey. 4. Rename the component “Body” to “Body-Aluminum”

HyperWorks 13.0



Step 4: Materials and Properties The best practice for model setup is to create your materials first, then your properties and then your mesh. This prevents the need to go back and assign properties later. HINT: You can use Model Browser + Entity Editor. 1. Create a Material for the Aluminum body of the satellite. 

Type: ISOTROPIC



Name: Aluminum



Card image: MAT1



E: 7.0e+04



NU: 0.330



RHO: 2.1e-09




2. Create a Material for the Electronics Packages. 

Type: ISOTROPIC



Name: Electronics



Card image: MAT1



E: 1000



NU: 0.300



RHO: Leave Blank for now. To be explained later

3. Create a Material for the Solar s. 

Type: ISOTROPIC



Name: Solars



Card image: MAT1



E: 2.0e+04



NU: 0.400



RHO: 1.0e-09

HyperWorks 13.0



4. Create a Property for the elements that will make up the Body of the satellite. 

Type: 2D



Name: Body-Aluminum



Card image: PSHELL



Material: Aluminum



Thickness: 5.00mm




5. Create a Property for the elements that will make up the Electronics. 

Type: 3D



Name: Electronics



Card image: PSOLID



Material: Electronics

6. Create a Property “Solars” for the elements that will make up the Solars. 

Type: 2D



Name: Solars



Card image: PSHELL



Material: Solars



Thickness: 1.50mm

HyperWorks 13.0



7. Create a Property for the elements that will make up the Engine. 

Type: 3D



Name: Engine



Card image: PSOLID



Material: Aluminum




8. Assign the properties to the appropriate components. HINT: The Components view can help.

Step 5: Mesh the part When solids are connected to surfaces, as is the case with the Electronics Packages and the Engine, it is often best to model the solid elements first. 1. Split the Engine into mappable regions and solid mesh with an element size of 100. Make sure to have a good circular pattern of elements. Also make sure you always have at least two elements through the thickness.

2. Solid Mesh the electronics Packages with a size of 100.

3. With the solids now meshed, mesh the body of the Satellite with an element size of 100. Assure good mesh pattern and quality as the quality of the analysis is highly dependent on mesh quality. HyperWorks 13.0



TIP: Avoid using automatic element cleanup as it can cause distortion in solid elements that are connected to shells. HINT: Differences in mesh densities for edges across from each other cause trias. Projecting points to edges can help mesh pattern problems around nodes enforced by fixed points.

4. Mesh the Solar s with an element size of 200.

Step 6: Import the Satellite Dish Often we can take information from previously run FEA’s and incorporate it into our FEA model. In this case, we will take a Satellite Dish that has been previously modeled and saved in an OptiStruct.fem format and import it into our model. 1. Import the file Dish.fem. This model has previously defined materials and properties.




2. that all the components have materials and properties assigned to them.

While the elements are properly imported into location, importing an FEM file will not connect the nodes of the imported model into the existing model. We need to attach the dish s to the body of the satellite. Equivalence the nodes at the 4 connection points where the Dish s meet the Body of the Satellite. HINT: Node equivalence is found on the Replace .

Step 7: Connect the Solar s to the Body 1. Using HyperBeam, create a BeamSection that is a thinwalled box that is 100mm on each side and 10mm thick. Name it Square_Solar_. 2. Create a PBAR property and assign the Square_Solar_ and assign the material Antenna that was imported in with the Dish. 3. Create a component for the Solar s. 4. Create BAR2 elements that connect the top and bottom innermost nodes to the nodes at the center of the connection holes you eliminated previously. Make sure they have the Solar property and align them with the Z axis. 5. Turn on the beam visualization mode to assure they were created properly.

HyperWorks 13.0



Step 8: Analysis Setup. By this stage all elements should be properly assigned properties and all properties should be assigned materials. Shell elements should have thicknesses and a PSHELL card and solids should have a PSOLID card. At this stage we begin the loading of the model. 422 HMD Introduction



The analysis we will be conducting is an Inertial Relief Analysis. This method was specifically designed to study spacecraft and aircraft in flight. The difficulty of studying situations such as those is the lack of a constraint system. Free flying objects are not constrained in a traditional manner so the SPC (Single Point Constraint) we have used up to now will not work for this type of study. Instead we shall define a structure of 1 constraints. These work to limit Rigid Body Motion (movement of the entire structure without deformation) but do not constrain the body against local deformation and thus are ideal for studying a free flying object. An inertial relief analysis can only have 6 TOTAL Degrees Of Freedom (DOF) constrained. When creating the 1 constraint system, the exact location of the constraints is not critical but typically follows this pattern: a) Create a 1 constraint at an extreme location of the part with X, Y and Z translational DOF constrained (1, 2 and 3). b) Pick another node at an extreme location and whichever direction that node is from the original node, that DOF is removed. For example, if to reach the second node you traveled in the Z axis direction, the Z DOF (3) would be removed making a new DOF of 1 and 2. c) For the final location, pick one more extreme position and remove the DOF that corresponds to the direction moved from the constraint created in step b. For example, if you traveled in the Y axis direction from the “b” constraint, you would remove the Y DOF (2) and would make the final constraint DOF 1 only. 1. Create a Load Collector called s. 2. Create the load types 1 constraints in the following pattern.

3. Now a force needs to be applied to the thruster. While it is not entirely representative of an engine giving thrust, what we will do is to place a distributed force on the nodes of the flat outer ring of the engine. The net force we will place on the thruster is 500N. HyperWorks 13.0



Because this net force is to be split across many nodes, we need to calculate the portion of the force that will be applied on each node. 4. Create a Load Collector called Thrust. 5. Count the number of nodes on the flat outer ring of the thruster. HINT: HyperMesh has a count function and selecting the nodes by plane makes counting them easy.

Number of nodes on Thruster _138___________ 6. Divide the Net Force (500N) by the number of nodes counted. 500N/138 (number of nodes) = 3.623 N (Force per node) 7. Create forces in the –Z direction at each node with the value calculated above. Now all of the loads are in place for our Inertial Relief Analysis. Next a Control Card must be set to tell the solver this will be that type of analysis.




8. In the PARAM control card, activate the INREL keyword and give it a value of -1. This value indicates it is an Inertia Relief Analysis with 1 constraints. For more information about the PARAM, or any other control card, consult the OptiStruct Format Reference Guide in the HELP Documentation.

The final step in setting up an analysis is to define a LOAD STEP. The load step is a combination of loads and constraints that represent an analysis in the solver. There can be multiple load steps in a single model containing any combination of defined loads and constraints. This saves time as multiple runs of a solver can be defined in one model. 9. Create a Linear Static Load Step that combines the s Constraints and the Thrust Force. HINT: that the s are 1 loads and NOT SPCs. Make sure you reference them in the correct location.

HyperWorks 13.0



The model is now set to run. Save it.

Step 9: Emergency Engineering Change At the last minute it has been decided that the Dish on this satellite is not large enough to properly broadcast back to Earth. Engineers have determined the Dish needs to be 4500mm in Diameter. Much time has been spent setting up the model. While it would be possible to remodel, remesh and re-setup the analysis, this would take time. Morphing is a perfect tool to quickly alter the already created mesh. 1. Using Morphing, create a domain and then change the dimension of the diameter of the Dish to 4500mm. HINT: It’s a 2D Domain.




Step 10: Run the Analysis With everything set up and the emergency engineering change dealt with, it is time to run the analysis. 1. Run the Analysis in OptiStruct.

Step 11: Post Process 1. In the HyperWorks Solver View dialog box, click the Results button to load the results in HyperView. 2. You can load a different input/result file clicking on Load model (load .fem as input file) and Load results (load .res as result file); click on Apply.

3. Change the animation type to Set Linear Animation Mode ( 4. Go to the contour (

).

).

5. Select the Result type to be Von Mises Stress (s). 6. Change Averaging method to Advanced.

HyperWorks 13.0



7. Click Apply.

Step 12: Design Changes As you can see from the results, the bottom of the satellite is not strong enough. 1. Using the tools within HyperMesh, increase the strength of the satellite. Some options are: 

Material Thickness



1D Reinforcement Beams.



Material Changes

Keep in mind though that it costs roughly $3,000-$4,000 per Pound to place something in Low Earth Orbit and closer to $10,000/lb for a Geosynchronous Orbit, so try to engineer the design and not just “beef it up!”



Appendix A: HyperMesh Desktop Customization

Appendix A

HyperMesh Desktop Customization

DEMO A1 - HyperMesh Desktop Customization Description The purpose of this example is to show how the can create and/or use a script in Hypermesh Desktop.  Add a button to the Page on the Utility Menu which executes the script modeltour.tcl.  This script is located in the installation under hm\scripts, so a path is not needed.  The name of the button should be “Model Tour”.  The pop up help string should be “Explore HyperMesh Session”.  The color and location are up to you.

HyperMesh commands used *createbutton()

TCL/TK commands used none

Hints On Windows, the working directory is located in the My Documents folder. Create a new text file called page.mac in this location and add the appropriate commands to make the button evaluate the tcl file.

HyperWorks 13.0


Appendix A: HyperMesh Desktop Customization

DEMO A2 - HyperMesh Desktop Customization Description The purpose of this example is to show how the can create and/or use a script in Hypermesh Desktop.  Add a pair of buttons to the Page on the Utility Menu. The first one shall call an editor with a certain file (tcl script “myScript.tcl”), the other one shall run this tcl script. This is a starting point to write scripts. The file name might be myScript.tcl in the local directory.  The names of the buttons should be "Test" and "Edit".  The pop up help strings should be “Test myScript.tcl" and "Edit myScript.tcl”.  The color and location as well as the macro names are up to you.

HyperMesh commands used *createbutton()

TCL/TK commands used none

Hints On Windows, the working directory is located in the My Documents folder. Create a new text file called page.mac in this location and add the appropriate commands to make the button evaluate the tcl file.

Step 1: Create the page.mac text file 1. On Windows, the working directory is located in the “My Documents” folder. 2. Create a new text file called page.mac in this location or use the previuos one. 3. Copy the tcl file located at ..\Model Files\CHAPTER-9-APPENDIX-A-HMDCUSTOM\A2\myScript.tcl in the “My Documents” folder.

Note: Please refer to the Demo Model Files folder and Online Help to get more details.



Appendix B: HyperWorks Collaboration Tools

Appendix B

HyperWorks Collaboration Tools & Assembly 1 – HyperWorks Collaboration Tools HyperWorks Collaboration Tools is a set of modules that deliver enterprise features and functionality to HyperWorks s. Tightly integrated into the HyperWorks suite of applications, HWE includes: With the HyperWorks Desktop collaboration tools, you can explore and organize your personal data, collaborate in teams, and connect to other data sources, such as corporate PLM systems to access CAD data.

1.1 - Benefits HyperWorks Collaboration Tools provides many benefits that challenge s and team managers to manage their CAD data. Some of these benefits are listed below: •

Well organized container for each project type

•

Centralized location of project data files

•

Easy access for team

•

Version controlled project data files

•

Does not require any additional software installation

•

Ability for team to view/modify project data files

•

Real time monitoring for individual projects

•

Integrated seamlessly within any Altair HyperWorks applications

•

Able to add new parsers to read in different metadata types

•

Customize toolbar to site’s specification

HyperWorks 13.0



1.2 - Components: Explore, Organize, Connect

• Explore CAE contents and metadata easily and quickly •

Integrated into all Desktop native file dialogs

•

Easily search & retrieve files

•

Automated indexing of selected folders

•

View properties associated with files, with automatic metadata extraction

• Organize CAE simulations in a content browser •

Organize simulation data and files into libraries

•

Browse local and shared libraries to find and retrieve contents

•

Retain pedigree via full version control

•

Synchronize to work with up to date information




• Connect to third-party PLM systems for CAD search and retrieve •

•

Connect to PLM systems •

Seamlessly connect to corporate PLM systems for CAD retrieval

•

Search & retrieve directly within PLM repository

•

Retrieve and load CAD files directly into HM

•

Initially available as OTB feature to pull CAD data from Teamcenter

Connect to other published contents •

Browse your teammates’ published resources

•

Existent Enterprise Data Sources (e.g. Material DB)

•

Create a generic “pull” connection

HyperWorks 13.0



•

Connect from HyperWorks Desktop to corporate PDM (Bi-Directional Integration) •

Search for Parts, CAD, BOM

•

Browse product structure for desired part(s)

•

and import directly into HyperWorks

•

Publish contents – meshes, solver decks, results, ... – back to PDM




1.3 - Terminology and Concepts Common terminology used with the HyperWorks Desktop collaboration features. Repository A Repository is where data, information, and associated files are located. •

There are two out-of-the-box repositories: •

My Computer is an unmanaged repository •

•

•

Unmanaged: Contents are not versioned and files are not moved from their current locations on the disk.

Personal is a managed repository •

Managed: Contents can be versioned, allowing for full lineage of the content and the files are moved to the library’s managed vault

•

Additional repositories can be added, such as corporate PLM systems

Repositories may contain one or more libraries

Library Libraries can be created within a repository to logically organize or group the contents stored within a repository by using the appropriate profile type •

There are three types of profiles •

CAE Profile (default) •

Contains out-of-the-box content definitions for CAE content types •

•

General Profile •

•

HyperMesh model, results file, solver deck

Will only contain non-content definitions

Managed Profile •

Contains out-of-the-box content definitions for material information

HyperWorks 13.0



Workspace •

Corresponds to a local directory where files are retrieved from the vault so they can be viewed and/or modified by s.

•

maintains knowledge of what contents have been retrieved from the repository at any given time.

•

For an unmanaged library the workspace is not used; since no file movement occurs

•

For a managed library the default workspace directory: C:/Documents and Settings/<>/hweDefaultWS

Vault An area, associated with a repository, where managed content files are moved and stored. •

Content Type

•

Contents stored within a library are typed, according to content definitions, based on the Altair Unified Data Model (UDM)

•

Contents are organized by the following methods: •

Category •

•

A special type of content which can be used to classify or organize other content

Folder •

A folder refers to the physical location of a file on the operating system, in a vault or a workspace




1.4 - Organize Browser & Interface HyperWorks Collaboration Tools features are mostly setup within the HyperWorks Organize Browser. The Organize Browser interface can be accessed within HyperWorks Desktop by clicking on the top window pull-down menu: View > Browsers > HyperWorks > Organize

Organize Browser - Interface

HyperWorks 13.0



Organize Browser – Toolbar

Organize Browser – Using and Setting Organize Browser Preferences s can set the Organize preferences such as: editing applications, diff applications, and map file extensions. To access the Organize preferences: 1. Right click within the Content browser to display the Context menu. 2. Click Set Preferences.




1.5 - Creating and Using a Personal Library Using the Collaboration tools within the Organize browser is very easy and simple to use. In this section, we will show you how to set up your first Personal library and populate it with CAE files. From there, we will show you some of the top level features how the Collaboration tools can help your CAE process. 

Creating a Personal CAE library



Adding CAE files to the Personal library



Searching for CAE files



Loading in a CAE model



Viewing Model Properties



Viewing Version History



Access to corporate material information



Guarantee that accurate properties are used in simulations



Seamless Integration within HyperWorks Desktop environment

HyperWorks 13.0



Accessibility •

Find what you’re looking for using full search and filter capabilities: • Search for materials based on robust set of properties • Simple keyword searches + advanced queries • Full text search – search within files • Filter materials by material type, solver type, etc.

Simple Query

•

Save commonly used queries for efficiency and reuse




Integration •

Content preview • Preview stress-strain curves • Overlay and compare curves

•

Access to material library during import process

•

Add new materials to library • Add individual materials interactively • Bulk load and add materials automatically • Extract material information from existing solver decks • Add new materials during material creation process

HyperWorks 13.0



•

Automatic metadata extraction

•

Maintain pedigree • Version history • Compare properties between versions • Compare files between versions

Use Cases & Connectors Examples •

Examples of Use Cases • Retrieve CAD from PLM System • Retrieve BOMs from PLM System • Publish FE Meshes/Solver Decks to PLM System • Publish CAE Results & Reports to PLM System • Retrieve Material information from Material Database

•

Examples of Existing Connectors • Siemens Teamcenter • PTC Windchill • Other PLM Vendors … • Material DB (e.g. Key To Metals) • Other 3rd Party Enterprise Applications




2 – HyperWorks Assembly Browser •

Build FE assembly models

•

Maintain properties from PDM  FE  PDM

•

Seamless Integration within HyperWorks Desktop environment

•

Batch meshing integration

HyperWorks 13.0



2.1 - Modules •

With the ever growing need to reduce model build times and manage models more effectively, a new and innovative approach to the way models are constructed within HyperMesh is underway.

•

A new HyperMesh entity, called the Module entity, will enable s to manage their model data in a modularized fashion.

•

Modularization allows for light-weight self-containment of parts & sub-assemblies

•

mod·ule [moj-ool] … a separable component, frequently one that is interchangeable with others, for assembly into units of differing size, complexity, or function.

•

Currently used by the Assembly browser •

NVH Director

•

Crash Profile

•

Teamcenter Integration

•

Modules are created when BOMs are loaded

•

In HW 13.0, we’ve taken the first steps to expose Modules as a new entity in HyperMesh.




Current Module •

The will be able to set a current module similar to current component from • Assembly Browser • Status Bar

HyperWorks 13.0



Organization within Modules •

Organize components, properties or materials from one module to another.

•

Show Contents - The will be able to review the contents of a module.

•

The will be able to set a current module similar to current component from •

Assembly Browser

•

Status Bar




Exercise B1 - Creating and Using a Personal Library In this exercise, you will learn to: 

Set up a first Personal library and populate it with CAE files



Search for files both in the Organize Browser



Load files into HyperMesh using the Organize Browser



Viewing Model Properties and Version History

Step1: Creating a Personal CAE library The first step to use any part of the Collaboration tools is to setup a library. The library will store all the files you wish to be part of that given library. Note: If you’ve upgraded your HyperWorks Desktop to version 13.0, then is highly recommended to remove C:\s\<name>\.Altair folder before to open HyperMesh Desktop. To create a Personal CAE library: 1. Create two directories as shown below: 

Create the folder “My_HWCT” under C:/  C:/My_HWCT



Create the folder “Libraries” under C:/My_HWCT  C:/My_HWCT/Libraries

2. The Organize Browser interface can be accessed within HyperWorks Desktop by clicking on the top window pull-down menu. Go to View >Browsers > HyperWorks > Organize to open the Organize Browser.

3. Click the Organize tab. 4. Click the Repository: arrow and select Personal from the list.

HyperWorks 13.0



5. Click the Library: arrow and select .

6. In the New Library dialog, fill in the fields as shown below:

7. Click OK.




Step2: Adding CAE files to the Personal library Once you have created your personal library, then the next step is to populate it with files. You can simply add files one at a time, or by directories. To add a directory of files to a given library: 1. Right click in the Content browser to access the Context menu.

HyperWorks 13.0



2. Click Add Files and Folders.

3. In the Select Files/Folders dialog, click Add Folder Files/Folders to Add” section.

icon in the “List of

4. In the Select File dialog box, locate the following folder: ..\Model Files\CHAPTER-10-APPENDIX-B-HWCTC\demos




5. Click OK. 6. Back in the Select Files/Folders dialog, click OK. 7. When the HyperWorks Organize confirmation dialog appears, click Ok. Wait for the indexing process to complete (it should take 10-20 seconds or few minutes, depending on your client.). Please wait till the entire directory has been indexed. Or you will not be able to complete the exercise. It will complain "Library is currently locked"

8. When the indexing process has completed (will take few minutes), a confirmation dialog will appear asking to refresh the Organize browser, click Yes. If the dialog will not appear just click on Refresh.

HyperWorks 13.0



Step3: Searching for CAE files Once your library has been populated with your CAE files, the Organize browser provides a simple searching tool to find any files in a given library. To perform a simple search for a CAE file within a given library: 1. Right click in the Content browser and then click Show Find from the Context menu.

2. Click the Options for searching

icon and click Use Wildcards.

3. In the Find: text box, enter: cleaned_up_geom*




4. Press Enter. 5. It should find and highlight the file: cleaned_up_geom.hm

Step4: Loading in a CAE model Once you have found the proper file, you can quickly load in the model by simply rightclicking on the file and click option to load in the file. To check-out a file and load it into a HyperMesh graphics area: 1. Right click on the cleaned_up_geom.hm file from the Content browser to access the Context menu. 2. From the Context menu, click Get.

HyperWorks 13.0



3. Right click on the cleaned_up_geom.hm file and from the Context menu click Load HM model.

4. The model will load automatically into the HyperMesh graphics area to the right.




Step5: Viewing Model Properties The Organize browser has a built-in feature that extracts the meta-data for each file that has been populated into a given library. While the files are being imported into a library, it also indexes and categorizes each of the file’s meta-data. These CAE meta-data can come in handy when you want to quickly review the properties of each file without loading into HyperWorks. To view the meta-data of any given file within a given library: 1. Click anyone of the files within the Content browser.

2. Click Show/Hide Properties

icon from the Content browser tool bar.

3. A sub should appear below to the Content browser showing the Properties .

HyperWorks 13.0



Step6: Viewing Version History On each instance when a file has been updated and checked-in; it will record a new version number into a library. This feature helps to track the number instances of that file has been checked-in. However, more importantly s can retrieve a particular version of that same file to review what changes were made. To review the version history of a file: 1. Click anyone of the files within the Content browser. 2. Right click on anyone of the files from the Content browser to access the Context menu. 3. From the Context menu, click Version History.

4. The Version History sub- should appear similar as below.

If this file has multiple in-checks, you will see the different version umbers under the Version column.

5. To return back to the main Organize browser, click on the blue arrow icon


.


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