LS-DYNA Solver Interface 8.0 Tutorials

HyperMesh 8.0 Tutorials LS-DYNA Solver Interface

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HyperMesh 8.0 Tutorials LS-DYNA Solver Interface General Introduction to HyperMesh - DYNA Interface - HM-4600 ........................... 1 Defining LS-DYNA Model and Load Data, Controls, and Output - HM-4605 ........ 5 Using Curves, Beams, Rigid Bodies Joints, and Loads in DYNA - HM-4610.....20 Model Importing, Airbags, Exporting Displayed, and Contacts using DYNA - HM-4615.............................................................................................................38 Rigid Wall, Model Data, Constraints, and Output using DYNA - HM-4620 .........46 Assemblies using DYNA - HM-4625 ..............................................................................56

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HyperMesh 8.0 Tutorials – LS-DYNA Solver Interface i Proprietary Information of Altair Engineering

General Introduction to HyperMesh - DYNA Interface - HM4600 In this tutorial, you will learn to understand the following components of the LS-Dyna interface: •

LS-DYNA FE input reader

•

LS-DYNA FE output template

•

LS-DYNA macro menu

•

LS-DYNA user profile

•

On-line help for the HyperMesh DYNA interface

HyperMesh’s LS-Dyna FE input translator, FE output template, macro menu, and user profile sets the foundation for using LS -Dyna with HyperMesh.

Tools DYNA Macro Menu The DYNA macro menu contains tools specific to using DYNA with HyperMesh. The menu has eight pages of tools. The pages and some menu tools are described below. Page

Page description

Geom/Mesh

Contains a set of macros related to working with model geometry, as well as a set for working with FE mesh.

User

For user-defined macros.

Disp

Contains a variety of macros that allow you to modify the graphical display of HyperMesh entities in several different ways such as: turn the display of individual entity types on and off, isolate only a specific entity type, or turn off the display of everything except entities of type.

QA/Model

Contains many tools to help you quickly review and clean up the quality of a pre-existing mesh.

Tools in the Tools page of the DYNA macro menu Error check

Checks your LS -DYNA deck for potential problems with components, properties, materials, rigids, joints, boundary conditions, and other entities and reports them on-screen. The report identifies the problem entity by ID, describes the error, and then enables you to isolate the entity in the model.

Part info

Summarizes a part’s statistics in a dialog.

Name mapping

Provides the ability to change names for various entity types to either the HyperMesh name or the LS -DYNA name, since both applications maintain separate names for parts.

Clone part

Clones a given part with the option of duplicating or reusing, Section and Material properties assigned to the existing part.

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HyperMesh 8.0 Tutorials – LS-DYNA Solver Interface 1 Proprietary Information of Altair Engineering

Tools in the Tools page of the DYNA macro menu Create part

Creates a new part, with the option of either creating new or reusing existing Section and Material properties through a single panel.

Part Replacement

Allows you to replace the elements in an existing component (*PART) with new elements; typically replacing a similar part remeshed or slightly reshaped.

Constrained Rgd Body

Summarize all the *CONSTRAINED_RIGID_BODIES and visualize the master and slave rigid bodies

Convert To Rigid

Converts a portion or whole model to rigid; creates *CONSTRAINED_RIGID_BODIES

Find Free

Identifies rigids and welds that have a free end

Find_Fix Free

Removes free ends of rigids and welds

Fix Incorrect

Merges *CONSTRAINED_NODAL_RIGID_BODIES that share common nodes

RLs with Sets

*CONSTRAINED_NODAL_RIGID_BODIES in HyperMesh 5.0 and older binary files updated to have a *SET_NODE_LIST (entity set). This allows you to have control over the set IDs.

Content Table

Summarize, create, and edit parts, sections in the model

Material Table

Summarize, create, and edit materials in the model

C-Interfto50

Converts display of DYNA contacts to HyperMesh 5.0 style for DYNA models created from HyperMesh 5.1 Release (no HyperMesh 5.1 DYNA update installed)

On-line Help HyperMesh on-line help describes how to create every supported DYNA card. To access the on-line help do the following: •

From the Help menu, click Interfaces. On the Contents tab in the pop-up window, go to Solver Interfacing in HyperWorks à LS-DYNA à HyperMesh à Supported LS-DYNA Keywords

2 HyperMesh 8.0 Tutorials – LS-DYNA Solver Interface Proprietary Information of Altair Engineering

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DYNA FE Input Translator The DYNA FE input translator imports DYNA input files. Two translators exist: FE input reader

Supported DYNA input file

DYNA KEY

Version 960 and 970 keyword format

DYNA SEQ

Version 936 sequential format

•

Select an input translator.

•

To import a DYNA input file, do one of the following: o Go to the File menu and point to Import, then point to Finite Element Model, and click LsDyna. o Click the file icon

, go to the import sub-panel, and select FE

DYNA FE Output Template A DYNA FE output template contains DYNA -specific formatting instructions that HyperMesh uses to create a DYNA input file. Several DYNA templates exist: FE output template

DYNA input file generated from template

ls-dyna\dyna.key

Version 970 keyword format

ls-dyna\curves.key

Version 970 keyword format for curves only

ls-dyna960\dyna.key

Version 960 keyword format

ls-dyna960\curves.key


ls-dyna_seq\dyna.seq

Version 936 sequential format

ls-dyna_seq\dyna.lrg

Version 936 sequential, large format

ls-dyna_seq\curves.seq

Version 960 sequential format for curves only

These templates are in the folder ALTAIR_HOME\templates\feoutput. •

To select an output template, do one of the following: o Click the file icon load

, go to the export sub-panel, select TEMPLATE, and click

o Press G on the keyboard to go to the Global panel and click Load. •

Set up your model for analysis with DYNA.

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DYNA User Profile To set the user profile, go to the Preferences menu and click User Profiles. Setting the user profile to DYNA saves you time and does the following: •

Sets the FE input reader to DYNA KEY;

•

Loads the dyna.key FE output template and DYNA macro menu;

•

Loads DYNA macro menu

•

Aligns the graphical user interface to focus on DYNA tools; Re-names and removes certain panels;

•

Enables the ALE setup panel.

Changing the DYNA user profile to another profile, such as OptiStruct, does not alter the DYNA model.


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Defining LS-DYNA Model and Load Data, Controls, and Output - HM-4605 In this tutorial, you will learn to: •

View DYNA keywords in HyperMesh as they will appear in the exported DYNA input file

•

Understand part, material, and section creation and element organization

•

Create sets

•

Create velocities

•

Understand the relation of DYNA entity type to HyperMesh element and load configurations

•

Create nodal single point constraints

•

Create contacts with set segment ID

•

Define output and termination

•

Export models to LS-DYNA formatted input files

Tools/Utilities •

LS-Dyna FE input translator

•

FE output template

•

LS-Dyna macro menu

•

User Profile

The above tools/utilities set the foundation for settings up an Ls-Dyna input deck with HyperMesh.

Exercises This tutorial contains the following exercises: Exercise 1: Define Boundary Conditions and Loads for the Head and A-Pillar Impact Analysis Exercise 2: Define Termination and Output for the Head and A-Pillar Impact Analysis

Section 1: Define Model Data Relation of *PART, *ELEMENT, *MAT, and *SECTION to Each Other *ELEMENT

EID

PID

*PART PID

SID

MID

*SECTION

SID

*MAT

MID

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A *PART shares attributes such as section properties (*SECTION) and a material model (*MAT). A group of elements (*ELEMENT) sharing common attributes generally share a common part id (PID). The figure below shows how the keywords *PART, *ELEMENT, *MAT and *SECTION relate to each other. A unique PID assigns a material id (MID) and a section id (SID) to an element. The figure below shows how the keywords *ELEMENT, *PART, *SECTION, and *MAT are organized in HyperMesh. *ELEMENT

EID

PID

Elements are organized into a component collector

*PART PID

SID

MID

Component collector’s card image

*SECTION

SID

Property collector with a property card image. Assign a property to a *PART by pointing to the property collector in the component collector’s card image.

*MAT

MID

Material collector with a material card image. Assign the material to the *PART by associating the material collector to the component collector.

Component, property and material collectors are created and edited from the collectors panel.

View DYNA Keywords in HyperMesh A HyperMesh card image allows you to view the image of keywords and data lines for defined DYNA entities as interpreted by the loaded template. The keywords and data lines appear in the exported DYNA input file as you see them in the card images. Additionally, for some card images, you can define and edit various parameters and data items for the corresponding DYNA keyword. Card image can be viewed using the Card Editor panel which can be accessed from either the Setup menu or from the Analysis page.

Create *MAT In HyperMesh, a *MAT is a material collector with a card image. To relate it to a *PART, the material collector is associated to a component collector. A material collector can be created from the Solver Browser or the Organize menu.

Update a Component’s Material Update any component with any material from the collectors panel, update sub-panel.

Material Table Utility This utility allows users to do the following: •

View a list of all existing materials in the model and attributes for them.

•

Create, edit, merge and check for duplicate materials.

This utility is located in the LsDyna macro menu under DYNA Tools page.


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Create *SECTION In HyperMesh, *SECTION is a property collector with a card image. This is created in the collectors panel, create sub-panel.

Exercise 1: Define Model Data for the Head and A-Pillar Impact Analysis. The purpose for this exercise is to help you become familiar with defining LS -DYNA materials, sections and parts using HyperMesh. This exercise comprises of setting up the model data for an LS -DYNA analysis of a hybrid III dummy head impacting an A-pillar. The head and A-pillar model is depicted below.

Head and A-pillar model (Ch2_Image1.tif) This exercise contains the following tasks. •

Define the material *MAT_ELASTIC for the A-pillar part and head part.

•

Define *SECTION_SHELL for the A-pillar.

•

Define *SECTION_SOLID for the head.

•

Define *PART for the A-pillar and the head.

Step 1: Load the LS-DYNA user profile . 1.

From the Preferences menu, click User Profiles…

2.

Select the LsDyna profile and click OK.

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Step 2: Retrieve the HyperMesh file head_start.hm. 1.

2.

Retrieve the .hm file can be in one of the following two ways: •

From File menu, point to Import, click on Hypermesh Model and select the .hm file.

•

From toolbar, click the Files icon select the .hm file

- Select hm file sub-panel – Click retrieve… and

Click return to go to the main menu.

Step 3: Define the material *MAT_ELASTIC for the A-pillar and head. 1.

Access the collectors panel in one of the following ways: •

From the Organize menu, click Collectors

•

From the toolbar, click collectors

2.

Go to create sub-panel.

3.

Set the collector type to materials.

4.

For name =, type elastic

5.

For card image =, select MATL1.

6.

Click create/edit to create the material and edit its card image.

7.

Click the [Rho] field and enter 1.2 E-6 for the density.

8.

For Young’s modulus [E], specify 210.

9.

For Poisson’s ratio [Nu], specify 0.26.

10. Click return to go to the collectors panel. 11. Remain in the collectors panel for the next step.

Step 4: Define *SECTION_SHELL with a thickness of 3.5 mm for the A-pillar. 1.

Change the collector type to properties.

2.

For name =, type section3.5.

3.

For card image =, select SectShll.

4.

For thickness =, enter 3.5

5.

Create/edit the property. Notice that a thickness (T1) of 3.5 is assigned to *SECTION_SHELL card.

6.

Return to the collectors panel.

7.

Stay in the collectors panel for the next step.


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Step 5: Define *SECTION_SOLID for the head. 1.

For name =, type solid.

2.

For card image =, select SectSld.

3.

Create/Edit the property.

4.


5.

Return to the main menu.

Step 6: Define *PART for the A-pillar. It’s *MAT_ELASTIC is the material collector named "elastic". Its *SECTION_SHELL is the property collector named "section3.5". 1.

Go to the collectors panel.

2.

Go to update sub-panel.

3.

Set the collector to comps.

4.

With the comps selector active, select the component pillar.

5.

For card image =, select Part.

6.

For material =, select elastic.

7.

For property =, select section3.5.

8.

Click update/edit. Notice that a *PART has been created and a section (SID) and a material (MID) has been assigned to it.

9.


10. Remain in the collectors panel for the next step.

Step 7: Define *PART for the head. It’s *MAT_ELASTIC is the material collector named "elastic". Its *SECTION_SOLID is the property collector named "solid". 1.

With the comps selector active, select the component head.

2.

For card image =, select Part.

3.

For material =, select elastic.

4.

For property =, select solid.

5.

Click update/edit. Notice that a *PART has been created and a section (SID) and a material (MID) has been assigned to it.

6.


7.

Return to the main panel.

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Step 8 (Optional): The exercise is complete. Save your work to a HyperMesh file.

Section 2: Define Boundary Conditions and Loads *INITIAL_VELOCITY_(Option) The table below describes DYNA keywords for defining initial velocity. DYNA keyword

Velocity applied to …

Setup in HyperMesh

*INITIAL_VELOCITY

set of nodes, *SET_NODE_LIST

Entity set of nodes,

*INITIAL_VELOCITY_GENE RATION

one *PART or set of parts, *SET_PART_LIST

Entity set of comps,

*INITIAL_VELOCITY_NODE

individual nodes

Created from velocity panel,

load collector with InitialVel card image

load collector with InitialVel card image

organized in load collector with no card image

*SET With the exception of *SET_SEGMENT, all *SET types are created from the entity sets panel in the BCs page. Graphically view a set’s contents with the review function in the entity sets panel. *SET_SEGMENT is created from the set_segments panel and is discussed in this chapter.

HyperMesh Entity Configurations and Types HyperMesh elements and loads have two identifiers: configuration and type. Configuration is a HyperMesh core feature. Type is defined by the loaded FE output template. A configuration can support multiple types. Before creating elements or loads, select the desired type from either the elem types panel (in the 1D, 2D and 3D pages) or the load types panel (in the BCs page). Use the load types panel only when creating loads directly on nodes or elements. For all other cases, the load is defined by creating a load collector with a card image. For example, *INITIAL_VELOCITY_NODE (applied directly to nodes) is created from the velocities panel while *INITIAL_VELOCITY (applied to nodes in a set) is a load collector with the InitialVel card image. You can see a list of element and load configurations in the elem types panel and the load types panel, respectively. These panels are pictured below.

elem types panel


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load types panel

Some element configurations are rigid and quad4. When a dyna.key template is loaded, types of the rigid configuration are RgdBody, ConNode and GenWeld (*CONSTRAINED_NODAL_RIGID_BODY, *CONSTRAINED_NODE_SET and *CONSTRAINED_GENERALIZED_WELD_SPOT). Similarly, some load configurations are force and pressure. Types of the pressure configuration are ShellPres and SegmentPre (*LOAD_SHELL_ELEMENT and *LOAD_SEGMENT). Most element and load configurations have their own panels. For example, rigids are created from the rigids panel and constraints are created from the constraints panel.

*BOUNDARY_SPC_(Option) The table below describes DYNA keywords for defining nodal single point constraints. DYNA keyword

Constraint applied to …

Setup in HyperMesh

*BOUNDARY_SPC_NODE

individual nodes

These are constraints created from the constraints panel and organized into a load collector with no card image.

*BOUNDARY_SPC_SET

a set of nodes *SET_NODE_LIST

This is an entity set of nodes referenced in a load collector’s BoundSpcSet card image.

*CONTACT and *SET_SEGMENT With the exception of *CONTACT_ENTITY, DYNA contacts are created from the interfaces panel in the Tool page. (*CONTACT_ENTITY is created from the rigid walls panel in the same page.) A DYNA contact is a HyperMesh group. When you want to manipulate a *CONTACT such as delete, renumber, or display it off, you select groups.

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DYNA Contact Master and Slave Types DYNA has multiple contact master and slave types from which to choose. The table below lists these types. While HyperMesh supports all of them, this chapter focuses on contacts with slave and master type 0, set segment id. Chapter three focuses on the other slave and master types.

*SET_SEGMENT and set_segment Panel *SET_SEGMENT is created from the set_segment (contactsurfs) panel. (The panel is named set_segment when the DYNA user profile is loaded.) Additionally, from this panel, you can add and remove elements from an existing *SET_SEGMENT and adjust the normal of segments without adjusting the normal of elements. The graphical representation of a contactsurf is pyramids, one pyramid for each segment. The orientation of a pyramid represents the normal orientation of the segment. By default, the orientation of a pyramid is the same as the normal of the element underneath. In the set_segment panel is the word contactsurfs and not the word set_segment. This is because contactsurfs is a HyperMesh configuration while set_segment is only the name of the panel for the DYNA user profile. This is important to know because when you want to manipulate a *SET_SEGMENT, such as delete, renumber, or display it off, you will select contactsurfs and not set_segment. A *SET_SEGMENT is specified in a *CONTACT from the interfaces panel, add sub-panel with master: or slave: type set to csurfs.


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Exercise 1: Define Boundary Conditions and Loads for the Head and A-Pillar Impact Analysis. The purpose for this exercise is to help you start becoming familiar with defining LS -DYNA boundary conditions, loads and contacts using HyperMesh. This exercise comprises of setting up the boundary conditions and loads data for an LS-DYNA analysis of a hybrid III dummy head impacting an A-pillar. The head and A-pillar model is depicted below.

Head and A-pillar model (Ch2_Image1.tif) This exercise contains the following three tasks. •

Define velocity on all nodes of the head with *INITIAL_VELOCITY

•

Constrain the pillar’s end nodes in all six degrees of freedom with *BOUNDARY_SPC_NODE

•

Define a contact between the head and A-pillar with *CONTACT_AUTOMATIC_SURFACE_TO_SURFACE

Step 1: Make sure the LS-DYNA user profile is still loaded. Step 2: Retrieve the HyperMesh file head_2.hm.

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Step 3: Create a node set, *SET_NODE_LIST, containing all the nodes in the head component. 1.

Access the entity sets panel in one of the following ways: •

From the Setup menu, click Entity Sets

•

From the Analysis page, click entity sets

2.

For name =, type Vel_Nodes.

3.

For card image. Select Node.

4.

With the nodes selector active, select nodes >> by collector and select the component head.

5.

Create the set.

6.


Step 4: Define the velocity. 1.

Enter the collectors panel, create sub-panel.

2.

Set the collector type to loadcols.

3.

For name =, type init_vel.

4.

For the card image = select InitialVel.

5.

Create/edit to create the load collector and edit its card image.

6.

For the node set id [NSID] select the entity set Vel_Nodes.

7.

For the initial velocity in the global x-direction, VX, specify 5.

8.


9.

Stay in the collectors panel for the next step.

Step 5: Create a load collector for the constraints to be created. Make sure the collector type is still set to loadcols. 1.

For name = type SPC.

2.

For creation method select no card image.

3.

Optionally select a color for the load collector.

4.

Create the load collector.

5.



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Step 6: Select BoundSPC for the HyperMesh constraint configuration. 1.

Access load types panel by one of the following ways: •

From the BCs menu, click Load Types

•

From the Analysis page, click load types

2.

For constraint = select BoundSPC.

3.


Step 7: Create constraints on the pillar’s end nodes. 1.

Access the constraints panel in one of the following ways: •

From the BCs menu, click Constraints

•

From the Analysis page, click constraints

2.


3.

Leave the entity selector set to nodes.

4.

Select nodes >> by sets and select the pre-defined entity set nodes for SPC. Notice the nodes at the pillar’s ends are highlighted.

5.

Leave all six degrees of freedom, dof1 thru dof6, active.

6.

Create the constraints.

7.


Step 8: Define a *SET_SEGMENT for the slave entities, the A-pillar elements. 1.

On the Analysis page, go to the set_segment panel, elems sub-panel.

2.

For name = type pillar_slave.

3.

For the card image select setSegment.

4.

Optionally select a color for the contactsurf.

5.

With the elems selector active, select elems >> by collector and then select the pillar component.

6.

Create the contactsurf.

7.

Review the contactsurf to make sure its pyramids are pointing out of the pillar.

8.

Stay in the set_segment panel for the next step.

Step 9: Define a *SET_SEGMENT for the master entities, the head elements. 1.

Select the solid faces sub-panel.

2.

For name = type head_master.

3.

For the card image = select setSegment.

4.


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5.

With the elems selector active, select elems >> by collector and then select the head component.

6.

Leave the toggle set to nodes on face.

7.

Click the yellow nodes selector to make it active.

8.

Select three nodes belonging to the same face of a solid element.

9.

For the break angle, leave is set to 30.

10. Create the contactsurf. 11. Review the contactsurf to make sure its pyramids are pointing out of the head. 12. Return to the main menu.

Step 10: Create a HyperMesh group with the SurfaceToSurface card image. 1.

Access the interfaces panel in one of the following ways: •

From the Setup menu, click Interfaces

•

From the Analysis page, click interfaces

2.


3.

For name = type contact.

4.

For type = select SurfaceToSurface.

5.

Create the group.

6.

Stay in the interfaces panel for the next step.

Step 11: Add the slave and master contactsurfs to the HyperMesh group. 1.

Select the add sub-panel.

2.

For the master type select csurfs.

3.

Click the contactsurfs selector and select the head_master contactsurf.

4.

Click update in the master: line, to the right of the yellow contactsurfs selector.

5.

For the slave type select csurfs.

6.

Click the contactsurfs selector in the slave: line and select pillar_slave.

7.

Click update in the slave: line.

8.


Step 12: Edit the group’s card image to define the AUTOMATIC option. 1.

Select the card image sub-panel.

2.

Edit the group’s card image.

3.

Under Options, select Automatic.

4.


5.



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Step 13: Review the group’s master and slave surfaces. 1.


2.

For name =, select contact.

3.

Click review. Notice the master and slave entities are temporarily displayed blue and red, respectively.

4.



Section 3: Define Control Cards and Specify Output *CONTROL and *DATABASE The *CONTROL cards are optional and can be used to change defaults and activate solution options, such as mass scaling, adaptive meshing and an implicit solution. It is advisable to define *CONTROL_TERMINATION in a model to specify a job’s end time. The *DATABASE cards are optional, but are necessary to obtain output files containing results. In HyperMesh, with the exception of the cards listed in the table below, all *CONTROL and *DATABASE cards are created from the control cards panel from either the Setup menu or the Analysis page. *DATABASE cards NOT created from control cards panel DYNA card

Panel used to create card

*DATABASE_CROSS_SECTION_(Option)

PLANE option, rigid walls panel SET option, interfaces panel

*DATABASE_HISTORY_(Option)

output blocks panel

*DATABASE_NODAL_FORCE_GROUP

interfaces panel

Exercise 2: Define Termination and Output for the Head and APillar Impact Analysis. The purpose for this exercise is to help you becoming familiar with defining LS-DYNA control data and output requests using HyperMesh. This exercise comprises of defining the termination and output for an LS-DYNA analysis of a hybrid III dummy head impacting an A-pillar. The head and A-pillar model is shown in the image below.

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Head and A-pillar model (Ch2_Image1.tif) This exercise contains the following four tasks. •

Specify the time at which LS-DYNA is to stop the analysis with *CONTROL_TERMINATION

•

Specify ASCII output with *DATABASE_(Option) cards

•

Specify the output of d3plot files with *DATABASE_BINARY_D3PLOT

•

Export the model to an LS -DYNA 970 formatted input file

Step 1: Make sure the LS-DYNA user profile is still loaded. Step 2: Retrieve the HyperMesh file head_3.hm. Step 3: Specify the time at which you want LS-DYNA to stop the analysis with *CONTROL_TERMINATION. 1.

The control cards panel can be accessed by one of the following ways, •

From the Setup menu, click Control Cards

•

From the Analysis page, click control cards

2.

Go to the next, next page.

3.

Select CONTROL_TERMINATION. A card image pops up.

4.

For the termination time of the analysis, ENDTIM , specify 2.5.

5.

Return to the control cards panel.

Step 4: Specify the output of d3plot files with *DATABASE_BINARY_D3PLOT. 1.

Go to the next page.

2.

Select DATABASE_BINARY_D3PLOT

3.

For the interval between outputs in the D3PLOT file, [DT], specify 0.1.

4.



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Step 5: Specify ASCII output with *DATABASE_(Option) cards. 1.

Go to the next page.

2.

Select DATABASE_OPTION.

3.

For the GLSTAT file, [GLSTAT], specify 0.1. This specifies the output of global data at every 0.1 ms.

4.

For the MATSUM file, [MATSUM], specify 0.1. This specifies the output of material energies every 0.1 ms.

5.

For the SPCFORC file, [SPCFORC], specify 0.1. This specifies the output of SPC reaction forces every 0.1 ms.

6.


7.


Step 6: Export the model as an Ls-Dyna keyword file. 1.

From the toolbar menu, enter the files

panel, export sub-panel.

2.

Make sure the template field shows the filename ls-dyna/dyna.key.

3.

Write as… head_complete.key.

4.

Click return to go to the main menu.

Step 7 (Optional): Submit the LS-DYNA input file to LS-DYNA 970. 1.

From the desktop’s Start menu, open the LS-DYNA Manager program.

2.

From the solvers menu, select Start LS-DYNA analysis.

3.

Load the file head_complete.key.

4.

Click OK to start the analysis.

Step 8 (Optional): Post-process the LS-DYNA results using HyperView. Step 9 (Optional): The exercise is complete. Save your work to a HyperMesh file.

Altair Engineering


Using Curves, Beams, Rigid Bodies Joints, and Loads in DYNA - HM-4610 In this tutorial, you will learn how to: •

Create XY curves to define non-linear materials

•

Define beam elements with HyperBeam

•

Create constrained nodal rigid bodies

•

Create joints

•

Define *DEFORMABLE_TO_RIGID

•

Define *LOAD_BODY

•

Define *BOUNDARY_PRESCRIBED_MOTION_NODE

•

Use the HyperMesh Content Table tool to review the model’s data

Tools The following tools are covered in this tutorial: •

DYNA Tools

•

Content Table

•

Curve Editor

Dyna Tools menu can be accessed from the View menu >> Utility Menu. Content Table is part of the DYNA Tools menu. With this tool, you can view a summary of the model’s parts as well as create and edit parts. Below is a list of the tool's functionality. •

Create a list of displayed or all parts and view them in the graphics area

•

Display parts with same section or material

•

Rename and renumber parts, sections and materials

•

Update thickness

•

Create new parts

•

Assign sections and materials to parts

•

Export table to file with comma separated format

In the Content Table window, Place the mouse handle over the button to see an explanation of each button. Below is a sample image of the Content Table.


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Curve Editor can be accessed by going to the Setup menu and click Curve Editor. The curve editor is a pop-up window that allows you to view and modify graphed curves in a more intuitive and holistic way than the individual xy plots panels provide. Below is a list of the tool’s functionality. •

Change curve attributes

•

Change graph attributes

•

Display curves in the graph area

•

Create a new curve

•

Delete a new curve

•

Rename a curve

Below is a sample image of the Curve Editor.

Exercises This tutorial contains the following exercises: Exercise 1: Define Model Data for Seat Impact Analysis Exercise 2: Define Boundary Conditions and Loads for the Seat Impact Analysis

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Process This section describes how to define model data.

*DEFINE_CURVE *DEFINE_CURVE defines a curve. Curves are often used to define non-linear materials and loads. There are a few methods for creating DYNA curves in HyperMesh. A few methods are described below. Method 1: Create using Curve Editor From the Setup menu, click Curve Editor. Method 2: Input XY Data from a File Create *DEFINE_CURVE by inputting an XY dat a file from the read curves or edit curves panel in the xy plots module on the Post page. The figure below displays a sample XY data file with a format supported by these panels. XYDATA, x1 y1 x2 y2 ENDDATA XYDATA, x1 y1 x2 y2 ENDDATA

XY Data File Format Engineers often receive test data in Excel file format. Data exported from Excel in comma or space delimited format can be read into HyperView. Data exported from HyperView in XY data format can be read into HyperMesh to create curves. In HyperView, from the Plot client, select Export Curves from the File pull-down menu. Select the XY Data format from the pop-up window. Method 3: Create with Math Expressions Create *DEFINE_CURVE with math expressions from the edit curves panel. From this panel, you can also create *DEFINE_CURVE with a math expression and an XY data file combination.

Plots The HyperMesh naming convention for curves is curveN where N is a number. Curves are displayed in plots. Display on and off a curve by displaying on and off its plot from the Display panel in the Tool bar area.


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Export Only XY Curves Export only curves to a DYNA input file using one of the following templates from the files panel, export sub-panel. HyperMesh template

DYNA input file generated from template

ls-dyna\curves.key


ls-dyna960\curves.key


These templates are in the folder ALTAIR_HOME\templates\feoutput. Import the exported file into HyperMesh from the files panel, import sub-panel.

*DEFINE_TABLE *DEFINE_TABLE defines a table. It consists of a *DEFINE_TABLE card followed by n lines of input. Each of the n additional lines define a numerical value in ascending order corresponding to a *DEFINE_CURVE input which follows the *DEFINE_TABLE command and the related input. In HyperMesh, *DEFINE_TABLE is created from a dummy *DEFINE_CURVE. Edit the dummy curve from the Card Editor panel. In the pop-up card image activate the DEFINE_TABLE option to create *DEFINE_TABLE and specify values and load curves. The figure below shows the *DEFINE_TABLE card image.

If, for example, ten stress-strain curves for ten different strain rates are given, HyperMesh will write ten cards to the DYNA input file after the first card for *DEFINE_TABLE. The ten corresponding *DEFINE_CURVE specifications will immediately follow in the exported input file.

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Beam Elements *ELEMENT_BEAM is created from the beams (bars) panel. (The panel is named beams when the DYNA user profile is loaded.) In this panel, you need to always specify node 3, which determines the initial configuration of the cross section. However, not every beam type requires node 3. You can suppress node 3 by card editing the beam elements from the Card Editor panel. Beam elements are organized into a component collector with the Part card image. Specify the THICKNESS and PID options by card editing the beam elements from the Card Editor panel.

*SECTION_BEAM *SECTION_BEAM is a property collector.

HyperBeam HyperBeam supports *SECTION_BEAM when ELFORM is 2 or 3. The HyperBeam panel is located in the Geom page. HyperBeam allows you to create a beam cross-section entity and this is saved to the HyperMesh database as a beamsec. Select a beamsec from the *SECTION_BEAM card image to populate its fields A, Iss, Itt, and Irr.

Nodal Rigid Bodies *CONSTRAINED_NODAL_RIGID_BODY can be created from Create Cards found under Tools menu. Below is an image of the rigids panel. When the panel option attach nodes as set is active, a *SET_NODE_LIST (entity set) containing all of the selected nodes is created. You can renumber the entity set from the renumbers panel. In the exported DYNA input file, the *SET_NODE_LIST immediately follows the *CONSTRAINED_NODAL_RIGID_BODY card.

Rigids panel

Joints All DYNA joints are created from Create Cards found under Tools menu. They are organized into a component collector with no card image. Unlike other 1D elements, you do not specify the DYNA joint type from the elem types panel. Rather, specify it in the panel used to create it, the fe joints panel. In the fe joints panel is the property= selector. As a DYNA user, you can disregard this selector. If the HyperMesh user profile is loaded, the panel also has the orientation option. As a DYNA user, you can disregard this option also.

Coincident Node Picking For DYNA joints, the nodal points in the nodal pairs should coincide in the initial configuration. The coincident picking option can be turned on from the options panel, modeling sub-panel. It allows you to graphically select a desired node from a stack of coincident nodes. This option also supports coincident picking for elements, loads, and systems.


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Create Coincident Nodes Create a node "like" an existing node from the create node panel in the Geom page. Select the type in sub-panel. Click as node, select a node in the graphics area and then click create.

*CONSTRAINED_JOINT_STIFFNESS *CONSTRAINED_JOINT_STIFFNESS_OPTION is a HyperMesh property collector with the JointStff card image.

*DEFORMABLE_TO_RIGID The table below lists the DYNA *DEFORMABLE_TO_RIGID keywords. DYNA keyword

Purpose

*DEFORMABLE_TO_RIGID

Switch parts to rigid at the start of the calculation

*DEFORMABLE_TO_RIGID_A UTOMATIC

Switch parts to rigid or to deformable at some state in the calculation

*DEFORMABLE_TO_RIGID_IN ERTIA

Define inertial properties for the new rigid bodies created when the deformable parts are switched

Below is the card format for specifying parts for these keywords: 1

2

PID

MRB

3

4

5

6

7

8

PID

is the ID of the slave part to be switched

MRB

is the part ID of the master rigid body to which the part is merged. This field exists only for *DEFORMABLE_TO_RIGID and for *DEFORMABLE_TO_RIGID_AUTOMATIC when the part is to be switched to rigid.

In HyperMesh, rather than specify one part at a time, you specify an entity set containing all of the desired slave parts. On export, the entity set’s part IDs are written to the DYNA input file according to the above card format.

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Exercise 1: Define Model Data for the Seat Impact Analysis. This exercise will help you continue to become familiar with defining LS-DYNA model data using HyperMesh. This exercise is comprised of defining and reviewing model data for an LS-DYNA analysis of a vehicle seat impacting a rigid block. The seat and block model is shown in the image below.

Seat and block model

Step 1: Load the LS-DYNA user profile. Step 2: Retrieve the HyperMesh file seat_start.hm. Step 3: Create an xy plot. 1.

Access the plot panel one of the following ways: •

From the Setup menu, point to XY plots, click Create Plots.

•

From the Post page, click xy plots and select plots panel.

2.

For name = type seat_mat.

3.

Verify the plot type is set to standard.

4.

Leave the like field empty. When an existing plot is selected, the new plot adopts its attributes.

5.

Create plot.

6.

Return to the xy plots module menu..


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Step 4: Input data from a file to create two stress-strain curves. 1.

Access the read curves panel one of the following ways: •

From the Setup menu, point to XY plots, click Read Curves.

•

From the Post page, click xy plots and select read curves panel.

2.

For plot =, leave it set to seat_mat.

3.

Browse for the file named seat_mat_data.txt.

4.

Input the file. Notice two curves are created and are named 0.001 strain rate for steel (curve1) and 0.004 strain rate for steel (curve2).

5.

Return to the xy plots module menu.

Step 5: Create a dummy xy curve to be used to create *DEFINE_TABLE. 1.

Access the edit curves panel one of the following ways: •

From the Setup menu, point to XY plots, click Edit Curves.

•

From the Post page, click xy plots and select edit curves panel.

2.

Go to the create sub-panel.

3.

For plot = select seat_mat.

4.

Activate the math option.

5.

In the x= field enter {0.0, 0.2}.

6.

In the y= field enter {0.4, 0.4}.

7.

Create the curve. Notice the curve is displayed in the seat_mat plot and has the name curve3.

8.


Step 6: Create *DEFINE_TABLE from the dummy curve. 1.

Access the card editor panel in one of the following ways: •

From the Setup menu, click Card Editor

•

From the toolbar, click the card editor icon

2.

Set the entity selector to curves.

3.

Select curve3.

4.

Edit the curve.

5.

Activate the option DEFINE_TABLE.

6.

In the card image, for the [ArrayCount], specify 2. This is the number of strain rate values to be specified.

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7.

For the strain rate VALUE(1) specify 0.001.

8.

For the strain rate VALUE(2) specify 0.004.

9.

For CurveId(1) select curve1.

10. For CurveId(2) select curve2. 11. Return to the main menu.

Step 7: Create the non-linear material. (*MAT_PIECEWISE_LINEAR_PLASTICITY) 1.

Do one of the following to create any LS-Dyna keyword card: •

From the Tools menu, click Create Cards

•

Right -click anywhere in Solver Browser window and click Create a new card

2.

From the Ls -Dyna keyword list, point to *MAT.

3.

Select *MAT_PIECEWISE_LINEAR_PLASTICITY.

4.

For name = type steel and click OK. Notice *MAT_PIECEWISE_LINEAR_PLASTICITY card is created.

5.

For density [Rho] specify 7.8 E-6.

6.

For Young’s Modulus [E] specify 200.

7.

For Poisson’s ratio [NU] specify 0.3.

8.

For yield stress [SIGY] specify 0.25.

9.

For the *DEFINE_TABLE id [LCSS] specify the curve3 (id=5).

10. Return to the collectors panel. 11. Return to the main menu.

Step 8: Update the base_frame and back_frame components with the new non-linear material. 1.

Click on Content Table found under DYNA Tools in the Utility Menu.

2.

From the Table menu, click Editable.

3.

Select the components base_frame and back_frame.

4.

For Assign Values:, select Material name

5.

For HM -Mats:, select steel

6.

Click Set.

7.

Click Yes to confirm.

8.

Close the Content Table window.


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Steps 9-12: Create a beam element, *ELEMENT_BEAM, to complete the seat’s back_frame connection to the side_frame on the left side. Step 9: Restore a pre-defined view for ease of following the next steps. 1.

From the View menu, click User Views. A window pops up.

2.

Click restore1 to see the beam view.

Step 10: Set the current component to beams. 1.

From the Preferences menu, click Global Parameters.

2.

For component =, select the beams component. This component has a pre-defined section, *SECTION_BEAM, with a tubular cross section associated to it.

3.


Step 11: Select the BEAM type for the HyperMesh beam configuration. 1.

Access the Element Types panel in one of the following ways: •

From the Mesh menu, click Element Types.

•

From the 1D page, click elem types.

2.

For beam = select BEAM.

3.


Step 12: Create the beam. 1.

From the 1D page, go to the beams panel.

2.

Go to the bar2 sub-panel.

3.

Click the leftmost switch and select node. A direction node is selected later to define the beam’s section orientation.

4.

Click the Node A selector to make it active.

5.

Select the center node of the left nodal rigid body for Node A. Node B is active now.

6.

Select the center node of the right nodal rigid body for Node B.

7.

Select any non-center node of one of the nodal rigid bodies for the direction node. Notice the beam is created.

8.


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Step 13: Restore a pre-defined view and display node IDs for ease of following the next steps. 1.

From the View menu, select User Views.

2.

Click restore2 to see the nodal rigid body view.

3.

On the Tool page, go to the numbers panel.

4.


5.

Click nodes and select by id. Enter 425-427, 431 and press ENTER.

6.

Display on the IDs.

7.


Step 14: Set the current component to welding. 1.

From the Preferences menu, click Global Parameters

2.

For component =, select the welding component.

3.


Step 15: Select the RgdBody type for the HyperMesh rigid configuration. 1.

Enter the Mesh menu, click Element Types.

2.

For rigid = select RgdBody.

3.


Step 16: Create the nodal rigid body (*CONSTRAINED_NODAL_RIGID_BODY). 1.

From the Tools menu, click Create Cards.

2.

From the Ls -Dyna keyword list, point to *CONSTRAINED

3.

Click on *CONSTRAINED_NODAL_RIGID_BODY

4.

Set nodes 2-n to multiple nodes.

5.

Select the beam’s free end for node1.

6.

Select nodes 425, 426, 427 and 431 for nodes 2-n.

7.

Leave active the attach nodes as set option.

8.

Create the nodal rigid body.

9.

Return to the main menu. A *CONSTRAINED_JOINT_STIFFNESS is not created; it is not needed for this joint to work.


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Step 17: Restore a pre-defined view and display node IDs for ease of following the next steps. 1.

From the View menu, click User Views.

2.

Click restore3 to see the joint view.

3.

From the Tool page, go to the numbers panel to display node IDs.

4.


5.

Click nodes and select by id. Type 1635, 1636 and press ENTER.

6.

Turn on the ids.

7.


8.

From the toolbar, click the Wireframe Elements (Skin Only) icon graphics mode.

to change to standard

Step 18: Activate coincident picking. 1.

Press O on the keyboard to access the options panel.

2.

Go to the graphics sub-panel.

3.

Activate coincident picking.

4.


Step 19: Set the current component to joint. 1.

From the Preferences menu, click Global Parameters.

2.

For component = select the joint component.

3.


Step 20: Create a revolute joint between two nodal rigid bodies (*CONSTRAINED_JOINT_REVOLUTE). The rigid bodies must share a common edge along which to define the joint. This edge, however, must not have the nodes merged together. The two rigid bodies will rotate relative to each other along the axis defined by the common edge. 1.


2.

From the Ls -Dyna keyword list, point to *CONSTRAINED

3.

Click on *CONSTRAINED_JOINT_REVOLUTE

4.

Set the joint type to revolute.

\

Node1 is active. 5.

Click on node 1635. Notice the coincident picking mechanism displays two nodes – 1635 and 1633.

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6.

Move the mouse to node 1635 in the coincident picking display and click on it to select it for node 1 in rigid body A. Node2 is now active.

7.

Click on node 1635 again to see the coincident picking mechanism and select node 1633 for node 2 in rigid body B. Node3 is now active.

8.

Click on node 1636. Two coincident nodes are displayed – 1636 and 1634

9.

Select node 1636 for node 3 in rigid body A. Node4 is now active.

10. Select node 1634 for node 4 in rigid body B. 11. Create the joint. 12. Return to the main menu.

Steps 21-23: Define *DEFORMABLE_TO_RIGID to set up the moving seat as rigid until the time of impact with the block, to reduce computation time. Step 21 Create an entity set that contains the components base_frame, back_frame, and cover. 1.

From the Setup menu, click Entity Sets.

2.

For name = type set_part_seat.

3.

For card image, select Part Notice the entity selector is set to comps.

4.

Select the base_frame, back_frame and cover components.

5.

Create the set.

6.


Step 22: Define *DEFORMABLE_TO_RIGID to switch the deformable seat to rigid at the beginning of the analysis. 1.


2.

From the Ls -Dyna keyword list, point to *DEFORMABLE_TO_RIGID.

3.

Click on *DEFORMABLE_TO_RIGID.

4.

For name =, type dtor.

5.

For the part set ID, [PSID], specify the set_part_seat set ID.

6.

For the master rigid body, [MRB], specify the back_frame component.

7.



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Step 23: Create *DEFORMABLE_TO_RIGID_AUTOMATIC to switch the rigid seat to deformable when contact between the seat and block is detected. 1.


2.

From the Ls-Dyna keyword list, point to *DEFORMABLE_TO_RIGID.

3.

Click on *DEFORMABLE_TO_RIGID_AUTOMATIC.

4.

For name =, type dtor_automatic.

5.

For the unique set number for this automatic switch set, [SWSET], enter 1.

6.

For the activation switch code [CODE] select 0. The switch will take place at [TIME1].

7.

For [TIME1] enter 175. The switch will not take place before this time.

8.

Activate R2D_Flag in the menu area. On export, the number of rigid parts to be switched to deformable is written to the R2D field (card 2, field 6). This number is based on the number of parts in the entity set you select next.

9.

Move the scroll bar on the left side of the card image down to see [PSIDR2D].

10. For the [PSIDR2D] field specify the set_part_seat set ID. 11. Return to the main menu.

Steps 24-28: Review the model’s data using the Content Table tool. •

From the Utility menu, click DYNA Tools, then click Content Table.

Step 24: Display only parts with a particular material (Ex: steel). 1.

From the Display menu, click By Material.

2.

Select material steel and click proceed. Notice that the GUI and the content table show only those components with material steel assigned. All other components get turned off.

3.

Follow the above steps to select components using By Properties and BY thickness option.

Step 25: Display all components. 1.

From the Display menu, click By Material. Notice now that the GUI and the Content Table show all components of the model.

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Step 26: Rename a part. 1.

From the Table menu, click Editable to make the content table editable. (All columns with a white background can be edited. Ex: Part name, Part id, Thickness etc.)

2.

Click on any part name field to edit it.

3.


4.

Click the disp icon

to go to the Display panel to notice the part’s new name.

Step 27: Renumber a part id. 1.

Click on the Part Id field.

2.

Type a number that does not conflict with the existing part IDs.

3.



Section 2: Define Boundary Conditions and Loads Exercise 2: Define Boundary Conditions and Loads for the Seat Impact Analysis. This exercise will help you continue to become familiar with defining LS-DYNA boundary conditions and loads using HyperMesh. In this exercise, you will define boundary conditions and load data for an LS-DYNA analysis of a vehicle seat impacting a rigid block. The seat and block model is shown in the image below.

Seat and block model 34 HyperMesh 8.0 Tutorials – LS-DYNA Solver Interface Proprietary Information of Altair Engineering

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This exercise contains the following three tasks. •

Define gravity acting in the negative z-direction with *LOAD_BODY_Z

•

Define the seat’s acceleration with *BOUNDARY_PRESCRIBED_MOTION_NODE

•

Export the model to an LS -DYNA 970 formatted input file and submit it to LS-DYNA

Step 1: Make sure the LS-DYNA user profile is still loaded. Step 2: Retrieve the HyperMesh file seat_2.hm. Step 3: Define gravity acting in the negative z-direction with *LOAD_BODY_Z. 1.


2.

From the Ls -Dyna keyword list, point to *LOAD.

3.

Click on *LOAD_BODY_Z.

4.

For name =, type gravity.

5.

For the load curve LCID, specify the ID of the curve named gravity curve.

6.

For the load curve scale factor [SF], specify 0.001.

7.


Steps 4-7: Define the seat’s acceleration with *BOUNDARY_PRESCRIBED_MOTION_NODE. Step 4: Create a load collector for the acceleration loads to be created. 1.

From the Organize menu, click Collectors.

2.

Set the collector type to load collectors.

3.

For name =, type accel.

4.

For creation method, select no card image.

5.

Optionally select a color for the load collector.

6.

Create the load collector.

7.


Step 5: Select the PrcrbAcc type for the HyperMesh acceleration configuration. 1.

From the BCs menu, click Load Types.

2.

For acceleration =, select PrcrbAcc.

3.


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Step 6: Create acceleration loads on nodes. 1.


2.

From the Ls -Dyna keyword list, point to *BOUNDARY

3.

Click on *BOUNDARY_PRESCRIBED_MOTION_NODE (Accl)

4.

With the nodes selector active, select nodes >> by sets.

5.

Select the pre-defined entity set accel_nodes.

6.

For magnitude, specify 0.001. This is the scale factor for the pre-defined curve to be specified in the next step for the acceleration loads. It will define the seat’s acceleration as a function of time.

7.

For the direction selector, select x-axis. This is the x-translational degree of freedom, EQ. 1.

8.

For the magnitude% =, specify 1.0E+7. This is the scale factor for the graphical representation of the acceleration loads. It does not affect the actual acceleration value.

9.

Create the acceleration loads.

10. Return to the main menu.

Step 7: Edit all of the acceleration loads simultaneously to specify the predefined xy curve named "acceleration curve" for them. 1.

From the Setup menu, click Card Editor.

2.

Set the entity selector to loads.

3.

With the loads selector active, select loads >> by collector.

4.

Select the load collector accel.

5.

For config =, select accels.

6.

For type =, leave it set to PrcrbAcc.

7.

Edit the acceleration loads.

8.

For load curve [LCID], specify the ID of the curve named acceleration curve.

9.

Return to the Card Editor panel.


Step 8: Export the model to an LS-DYNA 970 formatted input file. 1.

From the toolbar, enter the files

panel, and go to the export sub-panel.

2.


3.

Write as… seat_complete.key.

4.



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From the Start menu on your desktop, open the LS -DYNA Manager program.

2.


3.

Load the file seat_complete.key.

4.


Step 10 (Optional): View the results in HyperView. Step 11 (Optional): The exercise is complete. Save your work to a HyperMesh file.

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Model Importing, Airbags, Exporting Displayed, and Contacts using DYNA - HM-4615 In this tutorial, you will learn how to: •

Define *AIRBAG_WANG_NEFSKE for the airbag mesh geometry

•

Define an initial velocity of 3 mm/ms in the negative x-direction for the head with *INITIAL_VELOCITY_GENERATION

•

Define a contact between the airbag and head with *CONTACT_AUTOMATIC_SURFACE_TO_SURFACE

•

Define *CONTACT_AIRBAG_SINGLE_SURFACE for the airbag

•

Define a contact between the plate and the airbag with *CONTACT_NODES_TO_SURFACE

Import DYNA model Warning and Error Messages On import of a DYNA model, any HyperMesh warning and error messages are written to a file named dynakey.msg or dynaseq.msg, depending on the feinput translator used. This file is created in the same folder from which HyperMesh is started.

Unsupported Cards On import, few DYNA cards not supported by HyperMesh are written to unsupp_cards panel. This panel can be accessed from Setup menu by clicking on Control Cards. The unsupported cards are exported with the remaining model. Care should be taken if an unsupported card points to an entity in HyperMesh. An example of this is an unsupported material referenced by a *PART. HyperMesh stores unsupported cards as text and does not consider pointers.

LSTC Dummy Files You can read LSTC Hybrid III dummy files into HyperMesh by first converting the tree file to FTSS/ARUP tree file format.

Include Files HyperMesh supports *INCLUDE. In the files panel, import sub-panel is the option to read include files, skip include files and preserve include files. When include files are read, HyperMesh maintains the IDs of non-existing entities and does not use these IDs for new entities.

Export Displayed In the files panel, export sub-panel, you can toggle the all option to the displayed option to export only displayed nodes and elements. Only model data associated to the displayed nodes and elements are exported. This model data includes materials and their associated curves, properties, portions of contacts, and output requests.


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Create and Review Contacts The table below describes how all slave and master set types are created and specified in contacts. Slave and master set type

DYNA card

Panel used to create card

Equivalent type in interfaces panel, add sub-panel

EQ. 0: set segment id

*SET_SEGMENT

set_segment (contactsurfs) or …

csurfs

interfaces, add subpanel

entity

entity sets or…

sets


entity

entity sets or…

sets


comps

EQ. 1: shell element set id

*SET_SHELL_Option

EQ. 2: part set id

*SET_PART_LIST

EQ. 3: part id

*PART

collectors

comps

* EQ. 4: node set id

*SET_NODE_Option

entity sets or…

sets


entity


all

interfaces, add subpanel and then card image sub-panel

sets

* EQ. 5: include all * EQ. 6: part set id for exempted parts

*SET_PART_LIST

* For slave surface only

Add sub-panel While the interfaces panel, add sub-panel has several master and slave types - comps, sets, entity, etc. - to choose from in order to specify the DYNA master or slave set for a *CONTACT, only the valid master and slave types are selectable for the particular contact you are creating. When the master or slave type is set to comps and only one component is selected, the DYNA type is 3, part ID, and *PART is created. When multiple components are selected, the DYNA type is 2, part set ID, and *SET_PART_LIST is created. When the master or slave type is set to sets, only those sets valid for the particular contact you are creating are selectable. For example, for *CONTACT_NODES_TO_SURFACE, only a list of node sets is available for slave; you will not see a list of other set types, like element or part sets.

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Review Contacts You can review contacts with the review button in the interfaces panel, add sub-panel.

Exercise: Define Airbag, Velocity, and Contacts for the Airbag Analysis. This exercise will help you become familiar with defining LS-DYNA airbags using HyperMesh. It will also help you continue to learn how to define LS-DYNA loads and contacts using HyperMesh. In this exercise, you will define an airbag, velocity, and contacts for an LS -DYNA analysis of a head impacting an inflating airbag. The head and airbag model is shown in the image below.

Head and airbag model

Step 1: Load the LS-DYNA user profile. Step 2: Import the LS-DYNA input file, airbag_start.key. 1.

On the toolbar, go to the files panel

, then go to the import sub-panel.

Notice the FE radio button is active and next to the switch is DYNA KEY. This means the DYNA KEY import translator is selected. It was automatically selected when you loaded the Ls -Dyna user profile. 2.

Import… the file airbag_start.key.

3.



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Define *AIRBAG_WANG_NEFSKE for the airbag mesh geometry. Step 3: Create a set of parts, *SET_PART_LIST, containing the AirbagFront and AirbagRear components. 1.

On the Setup menu, click Entity Sets.

2.

For name =, type airbag_set.

3.

For card image, select Part.

4.

Click on Comps and select the components AirbagFront and AirbagRear.

5.

Create the set.

6.


Step 4: Define the airbag (*AIRBAG_WANG_NEFSKE). 1.

On the Tools menu, click Create Cards.

2.

From the Ls -Dyna keyword list, point to *AIRBAG

3.

Click on *AIRBAG_WANG_NEFSKE.

4.

For name =, type airbag.

5.

With the set selector active, select the entity set airbag_set. The parts in this set define the airbag’s geometry.

6.

Click update.

7.

Edit the control volume.

8.

Enter the following data in the card image.

9.

Value

Field

Parameter description

1023.0

CV

Heat capacity at constant volume

1320.0

CP

Heat capacity at constant pressure

780.0

T

Temperature of input gas

curve id 1

LCMT

Load curve specifying input mass flow rate

1.0

C23

Vent orifice coefficient

curve id 2

LCA23

Load curve defining vent orifice area as a function of pressure

1.0

CP23

Orifice coefficient for leakage

1.0E-4

PE

Ambient pressure

1.0E-9

RO

Ambient density

1.0

GC

Gravitational conversion constant


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Step 5: Define an initial velocity of 3 mm/ms in the negative x-direction for the head with *INITIAL_VELOCITY_GENERATION. 1.

On the Tools menu, click Create cards.

2.

From the Ls -Dyna keyword list, point to *INITIAL.

3.

Click on *INITIAL_VELOCITY_GENERATION.

4.

For name, type velocity.

5.

Under STYP, select Part ID for the set type.

6.

In the PID field, specify the Head component’s id.

7.

For velocity in the X direction VX, specify –3.

8.


Define a contact between the airbag and head with *CONTACT_AUTOMATIC_SURFACE_TO_SURFACE. Step 6: Create a HyperMesh group with the card image SurfaceToSurface. 1.


2.

From the Ls -Dyna keyword list, point to *CONTACT.

3.

Click on *CONTACT_AUTOMATIC_SURFACE_TO_SURFACE.

4.

For name, type Airbag_Head.

5.

Return to the Interfaces panel.

Step 7: Specify the head to be the master surface with surface type 3, part id. 1.


2.

Set the master surface type to comps.

3.

Select the Head component.

4.

Update the master selection.

5.

Stay in the add sub-panel for the next step.

Step 8: Specify all of the airbag to be the slave surface with surface type 2, part set id. 1.

Set the slave surface type to sets.

2.

Select the pre-defined entity set airbag_set (*SET_PART_LIST). This set contains the AirbagFront and AirbagRear components.

3.

Click update in the slave line to update the slave selection.

4.



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Step 9: View the master and slave entities. 1.

Click review. Notice the master and slave entities are temporarily displayed blue and red, respectively. All other entities are temporarily displayed grey.

2.


Step 10: Define *CONTACT_AIRBAG_SINGLE_SURFACE for the airbag. 1.


2.


3.

Click on *CONTACT_AIRBAG_SINGLE_SURFACE.

4.

For name, type airbag.

5.


6.


Step 11: Define all of the airbag to be the slave surface with slave set type 2, part set id. 1.


2.

Set the slave: surface type to sets.

3.

Select the pre-defined entity set airbag_set (*SET_PART_LIST).

4.

Update the slave selection.

5.


Step 12: View the slave entities. 1.

Click review. Notice the slave entities are temporarily displayed red. All other entities are temporarily displayed grey.

2.


Define a contact between the plate and the airbag with *CONTACT_NODES_TO_SURFACE. Step 13: Due to the dynamics of the contact, define the AirbagRear component to be the master surface with master type 0, set segment id. 1.

On the Setup menu, click Contact Surfaces

2.

Select the elems sub-panel.

3.

For name=, type AirbagRear_master.

4.

For card image =, select setSegment.

5.


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6.

With the elems selector active, select elems >> by collector.

7.

Select the AirbagRear component.

8.

Create the contactsurf. Notice the contactsurf’s pyramids point into the airbag. They should point out. In the next step you will reverse their direction.

9.

Stay in the set_segment panel for the next step.

Step 14: Reverse the contactsurf’s pyramids so they point out of the airbag. 1.

Select the adjust normals sub-panel.

2.

With the contactsurf active, select AirbagRear_master.

3.

Toggle from by elems to all elems.

4.

Reverse normals.

5.


Step 15: Create *CONTACT_NODES_TO_SURFACE card. 1.


2.


3.

Click *CONTACT_NODES_TO_SURFACE.

4.

For name, type Airbag_Plate.

5.


6.


Step 16: Specify the AirbagRear_master contactsurf for the contact’s master surface. 1.


2.

Set the master surface type to csurfs.

3.

Select the contactsurf AirbagRear_master.

4.

Update the master selection.

5.


Step 17: Define the plate to be the contact’s slave surface with slave type 4, node set id. 1.

Set the slave surface type to entity.

2.

Select nodes >> by collector.

3.

Select the RigidPlate component.

4.

Add the slave selection.

5.



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Step 18: View the master and slave entities. 1.

Click review. Notice the master and slave entities are temporarily displayed blue and red, respectively. All other entities are temporarily displayed grey.

2.



From the toolbar, enter the files panel

, export sub-panel.

2.


3.

Verify toggle is set to all.

4.

Write as… airbag_complete.key.

5.



From the Start menu, open the LS-DYNA Manager program.

2.


3.

Load the file airbag_complete.key.

4.



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Rigid Wall, Model Data, Constraints, and Output using DYNA - HM-4620 In this tutorial, you will learn how to: •

Create *PART_INERTIA for the component vehicle mass to partially take into account the inertia properties and mass of the missing parts.

•

Create velocity on all nodes but the barrier nodes with *DEFINE_BOX and *INITIAL_VELOCITY.

•

Make the closest row of nodes of the crash boxes a part of the vehicle mass rigid body with *CONSTRAINED_EXTRA_NODES.

•

Create a contact between the crash boxes, the bumper and the barrier with *CONTACT_AUTOMATIC_GENERAL.

•

Specify the output of resultant forces for a plane on the left interior and exterior crash boxes with *DATABASE_CROSS_SECTION_PLANE.

•

Create a stationary rigid wall to constrain further movement of the barrier after impact with *RIGIDWALL_PLANAR_FINITE.

•

Specify some nodes to be output to the ASCII NODOUT file with *DATABASE_HISTORY_NODE.

*PART_INERTIA The INERTIA option allows inertial properties and initial conditions to be defined rather than calculated from the finite element mesh. This applies to rigid bodies only. When importing a DYNA model into HyperMesh, the *PART_INERTIA IRCS parameter value is changed from 0 to 1. (The inertia components are changed from global to local axis.) This allows inertia components to be automatically updated when *PART_INERTIA elements are translated or rotated. When selecting *PART_INERTIA elements to translate or rotate, select elements by comp. This selection method ensures the inertia properties are automatically updated.

*CONSTRAINED_EXTRA_NODES This card defines extra nodes to be part of a rigid body. In HyperMesh, it is created from the Solver Browser.

*DATABASE_CROSS_SECTION_(Option) *DATABASE_CROSS_SECTION_(Option) defines a cross section for resultant forces written to the ASCII SECFORC file. The options are PLANE and SET. For the PLANE option, a cutting plane must be defined. For best results, the plane should cleanly pass through the middle of the elements, distributing them equally on either side. The SET option requires the equivalent of the automatically generated input via the cutting plane to be identified manually and defined in sets. All nodes in the cross-section and their related elements contributing to the cross-sectional force resultants should be defined in sets. *DATABASE_CROSS_SECTION_SET and *DATABASE_CROSS_SECTION_PLANE are created from the Solver Browser.. Like the interfaces panel, anything created from the rigid walls panel is a HyperMesh group. Thus, to rename, renumber or delete a *DATABASE_CROSS_SECTION card, select groups from the rename, renumber or delete panel.


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*RIGIDWALL A *RIGIDWALL provides a method for treating contact between a rigid surface and nodal points of a deformable body. In HyperMesh, *RIGIDWALL keyword cards are created from the Solver Browser.

Exercise: Set Up the Bumper Model for Impact Analysis. This exercise will help you become familiar with defining LS-DYNA rigid walls using HyperMesh. It will also help you continue to learn how to define LS-DYNA model data, constraints, and output using HyperMesh. In this exercise, you will define model data, loads, constraints, a rigid wall, and output for an LSDYNA analysis of a bumper in a 40% frontal offset crash. The bumper model is shown in the image below.

Bumper model

Step 1: Load the LS-DYNA user profile. 1.

On the Preferences menu, click User Profiles.

2.

Select LsDyna.

Step 2: Import the LS-DYNA model bumper_start.key. 1.

From the toolbar, enter files

2.

Import… the LS-DYNA model file bumper_start.key.

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panel, import sub-panel.


Step 3: Define *PART_INERTIA for the vehicle mass component to partially take into account the inertia properties and mass of the missing parts. 1.

On the Setup menu, click Card Editor

, and select Comps.

2.

Click on Comps and select the existing component vehicle mass.

3.

Edit the component’s card image.

4.

Under Options, select Inertia.

5.

For the center of mass coordinates XC, YC, ZC, specify 700, 0, 170, respectively.

6.

For translational mass TM, specify 800.

7.

For the components of the inertia tensor, specify the following: IXX

IXY

IXZ

IYY

IYZ

IZZ

1.5E+07

-5.0E+03

-8.0E+06

5.0E+07

-900

6.0E+07

8.

For the initial translational velocity along the X-axis, VTX, specify -10.

9.

Return to the Card Editor panel.


Step 4: Create a *DEFINE_BOX that contains all nodes but the barrier nodes. 1.


2.

From the Ls -Dyna keyword list, point to *DEFINE and click on *DEFINE_BOX.

3.

For the block name=, type box velocity.

4.

Make sure card image=, is set to DefineBox.

5.

Optionally select a block color.

6.

Toggle lower bound from corner node to x=, y=, z=.

7.

Specify the lower and upper bounds as follows: lower bound

upper bound

-530

200

-800

800

0

300

8.

Create the box.

9.

Activate review nodes to see the nodes included in the box.



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Step 5: Create initial velocity on all nodes but the barrier nodes. 1.


2.

From the Ls -Dyna keyword list, point to *INITIAL and click on *INITIAL_VELOCITY.

3.

For Name, type velocity and click ok.

4.

For the initial velocity in the global X direction, VX, specify –10.

5.

In the BOXID field, specify the box velocity id.

6.


Step 6: View the closest nodes which are in the pre-defined node entity set (*SET_NODES_LIST) named Constrain Vehicle. 1.

On the Setup menu, click entity sets.

2.

Click review.

3.

Toggle from display RLs to hide RLs. This filters all nodal rigid body sets from the list.

4.

Select the Constrain Vehicle set. Notice the set’s nodes are highlighted.

5.


Step 7: Create *CONSTRAINED_EXTRA_NODES_SET. 1.


2.

From the Ls -Dyna keyword list, point to *CONSTRAINED and click on *CONSTRAINED_EXTRA_NODES_SET.

3.

For Name, type ExtraNodes and click ok.

4.

For the part id (PID) of the rigid body to which the nodes will be added, specify the vehicle mass component’s ID.

5.

Return to the interfaces panel.

6.


Step 8: Define the nodes in the Constrain Vehicle set to be a part of the vehicle mass rigid body. 1.


2.

Make sure name=, is set to ExtraNodes.

3.

Set the slave type to sets.

4.

Select the Constrain Vehicle set.

5.


6.


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Step 9: View the extra nodes that are a part of the vehicle mass rigid body. 1.

Click review. Notice the extra nodes are temporarily displayed red while the PID (vehicle mass) is temporarily displayed blue. All other entities are temporarily displayed grey.

2.


Step 10: Create an entity set, *SET_PART_LIST, for just the vehicle mass component. All other components not in this set will be included in the contact. 1.


2.

From the Ls -Dyna keyword list, point to *SET and click *SET_PART_LIST (Non-Ordered).

3.

For name=, type Exempt Parts.

4.

Make sure card image, is set to Part.

5.

With the comps selector active, select the vehicle mass component.

6.

Create the set.

7.


Step 11: Create *CONTACT_AUTOMATIC_GENERAL contact. 1.


2.

From the Ls -Dyna keyword list, point to *CONTACT and click on *CONTACT_AUTOMATIC_GENERAL.

3.

For name=, type impact.

4.

Create the group.

5.

Return to the interfaces panel.

6.


Step 12: Define the slave surface with slave set type 6, part set id for exempted parts. 1.


2.

Make sure name=, is set to impact.

3.


4.

Select the Exempt Parts set.

5.


6.

Select the card image sub-panel.

7.

Edit the group.

8.

Activate the option ExemptSlvPartSet. Notice the slave surface type SSTYPE value changes from 2 (part set ID) to 6 (part set ID for exempted parts).


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9.

For the static coefficient, FS, specify 0.15.

10. Return to the interfaces panel. 11. Return to the main menu.

Step 13: Create an entity set, *SET_PART_LIST, to specify the elements that will contribute to the cross-sectional force results. 1.

In the Analysis page, enter the entity sets panel.

2.

For name=, type XsectionPlane-Parts.

3.

For card image, select Part.

4.

With the comps selector active, select the components interior crashbox and exterior crashbox.

5.

Create the set.

6.


Step 14: Define a section by creating *DATABASE_CROSS_SECTION_PLANE. 1.


2.

From the Ls -Dyna keyword list, point to *DATABASE and click on *DATABASE_CROSS_SECTION_PLANE.

3.

For Name, type Xsection_Plane and click ok.

4.

Create the group.

5.

Return to the rigid walls panel.

6.

Stay in the rigid walls panel for the next step.

Step 15: Define the location and size of the section’s plane. 1.

Select the geom sub-panel. In this sub-panel, the plane’s origin (the tail of the normal vector) is defined by a base node. Create a node from the create nodes panel by following steps 2 - 5 below and then select it for the base node.

2.

Make sure name=, is set to XSection-Plane

3.

Press the F8 key to enter the create nodes panel in the Geom page. The rigid walls panel, geom sub-panel is interrupted.

4.

Select the type in sub-panel.

5.

For x=, y= and z=, enter the values –320, -500 and 100, respectively.

6.

Create node. Notice the node is created and is displayed.

7.

Return to the geom sub-panel.

8.

With the base node selector active, select the node just created.

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9.

Switch normal vector: to x-axis. This defines the wall’s normal vector.

10. Leave shape set to plane. 11. Toggle from infinite to finite. 12. Toggle from corners to dist/axis. 13. Switch local x axis: to y-axis. This defines the edge vector L. 14. For len x= and len y=, specify 100 and 200, respectively. Doing this defines the extent of the section. The values are the length of the edges a and b in the L and M directions, respectively. 15. Update the group. 16. Stay in the rigid walls panel for the next step.

Step 16: Specify the parts slave to the rigid wall. 1.


2.


3.

Select the set XsectionPlane-Parts.

4.


5.


Step 17: View the entities slave to the rigid wall. 1.

Click review. Notice the slave entities are displayed red while the rigid wall is displayed blue. All other entities are temporarily displayed grey.

2.


Step 18: Create a *DEFINE_BOX containing the nodes making up the barrier and bumper’s left side. These nodes will be slave to the rigid wall. 1.


2.

From the Ls -Dyna keyword list, point to *DEFINE and click on *DEFINE_BOX.

3.

For block name=, type half model.

4.

For card image =, leave it set to DefineBox.

5.

Optionally select a block color.


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6.

Specify the lower and upper bounds as follows: lower bound

upper bound

-600

-460

-800

0

0

400

7.

Create the box.

8.

Activate the option review nodes to see the nodes included in the box.

9.


Step 19: Define a HyperMesh group by creating *RIGIDWALL_PLANAR_FINITE. 1.


2.

From the Ls -Dyna keyword list, point to *RIGIDWALL and click on *RIGIDWALL_PLANAR_FINITE.

3.

For Name, type wall.

4.

Create the group.

5.


6.


Step 20: Define the location and size of the rigid wall. 1.

Select the geom sub-panel. In this sub-panel, the rigid wall’s origin (the tail of the normal vector) is defined by a base node. Create a node from the create nodes panel by following steps 2 - 5 below and then select it for the base node.

2.

Make sure name=, is set to wall.

3.

Press the F8 key to enter the create nodes panel.

4.

Select the type in sub-panel.

5.

For x=, y= and z=, enter the values –600, -750 and 90, respectively.

6.

Create node. Notice the node is created and is displayed.

7.

Return to the rigid walls panel, geom sub-panel.

8.

With the base node selector active, select the node that was created in step 5.

9.

Switch normal vector: set to x-axis.

10. Leave shape: set to plane. 11. Toggle from infinite to finite. 12. Toggle from corners to dist/axis. 13. Select y-axis for local x axis.

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14. For len x= and len y=, specify 615 and 250, respectively. These values define the extent of the wall. They are the length of the edges l and m, respectively. 15. Update the group. 16. Stay in the rigid walls panel for the next step.

Step 21: Edit the card image for the rigid wall to specify the nodes in the *DEFINE_BOX half model as slave to the rigid wall. 1.

Select the card sub-panel.

2.

Edit the group.

3.

For the BOXID, specify the ID of the box half model.

4.

For the friction coefficient, FRIC, specify 1.0.

5.


6.


Step 22: Specify some nodes to be output to the ASCII NODOUT file with *DATABASE_HISTORY_NODE. 1.

In the Analysis page, enter the output block panel.

2.

For the output block name, type nodeth.

3.

Set the entity selector to nodes.

4.

Select a few nodes of interest from the graphics area.

5.

Create the output block.

6.



From the tool bar, enter the files panel

, export sub-panel.

2.


3.

Write as… bumper_complete.key.


From the Start menu, open the LS-DYNA Manager program.

2.


3.

Load the file bumper_complete.key.

4.



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Assemblies using DYNA - HM-4625 In this tutorial, you will learn how to: •

Weld between geometry surfaces and shell elements

•

Weld using a master connectors file and duplicating and reflecting connectors

•

Create connectors from existing welds to create new welds of a different type

•

Swap welded part

•

Understand why connectors may fail to realize and how to correct the problems

Tools The Connectors module can be accessed by: •

On the Setup menu, point to Connectors, and click Connectors

•

Go to the 1D, 2D, or 3D page, click connectors

Exercises This tutorial contains the following exercises: Exercise 1: Weld Between Geometry Surfaces and Shell Elements Exercise 2: Weld Using a Master Connectors File and Duplicating and Reflecting Connectors Exercise 3: Create Connectors from Existing Welds to Create New Welds of a Different Type Exercise 4: Swap Welded Part Exercise 5: Troubleshoot Failure of Connectors to Realize The first four exercises will help you become familiar with connecting (welding) an assembly of parts, using various methods, and replacing parts with newer, similar parts and updating their affected connections. The fifth exercise will help you become familiar with troubleshooting failure of connectors to realize. The part assembly used in the first four exercises is depicted in the image below. A very brief description of the corresponding exercises follows. (The exercises are independent of each other.)


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Exercise 1: Weld Between Geometry Surfaces and Shell Elements. The purpose of this exercise is to become familiar with creating welds at pre-defined weld points between geometry surfaces and shell elements. In this exercise, first weld the two front trusses depicted in the image below. Do this as follows: 1) create connectors between their geometry surfaces at pre-defined weld points, and 2) realize the connectors into two node weld elements.

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Second, weld the two front trusses to the reinforcement plate depicted in the image below. Do this as follows: 1) create connectors between their shell elements at pre-defined weld points and, 2) realize the connectors into two node weld elements.

Step 1: Retrieve and view the model file frame_assembly_1.hm. 1.

Retrieve the model file, frame_assembly.hm.

2.

Take a few moments to observe the model using various visual options available in HyperMesh (rotation, zooming, etc.).

3.

Go to the Preferences menu, click User Profiles.

4.

Select LsDyna.

Step 2: Create welds between the geometry for the two front trusses at the pre-defined weld points. 1.

On the Setup menu, point to Connectors and click on Spot.

2.

Go to the spot subpanel.

3.

On the header bar, verify that the current component is Con_Frt_Truss.

4.

Switch the location: entity selector to points.

5.

Select the six pre-defined weld points by selecting points >> by collector and selecting the component Con_Frt_Truss.

6.

Click select.

7.

For connect what:, select the components Front_Truss_1 and Front_Truss_2.


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8.

For connect what:, toggle elems to geom.

9.

For tolerance = specify 5.

10. For type=, select weld. 11. Click create.

The six connectors are automatically created and realized. The green connectors indicate that the creation of the weld entity was successful. The connectors are organized as geometry (not elements) in the current component collector, Con_Frt_Truss.

There are three states of connectors: realized (green )unrealized (yellow )and failed (red ).The color of the connectors change from yellow to green (if created manual), indicating they are realized into weld elements. As mentioned above, if created automatically they will be green immediately as there is no interim unrealized (yellow) state. Fixed points were added to the surfaces at the ends of the weld elements to guarantee connectivity between the weld elements and the shell mesh that will be created on the surfaces.

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Step 3: Create a shell mesh on the two front truss components. 1.

Press F12 to go to the automesh panel.

2.

Go to the size and bias sub-panel.

3.

Select surfs >> by collector and select Front_Truss_1 and Front_Truss_2.

4.

For elem size = specify 10.

5.

For mesh type, select mixed.

6.

Ensure the toggle is set to elems to surf comp. (It currently may be elems to current comp.)

7.

Select the mesh mode automatic. (It currently may be interactive. )

8.

Mesh the surfaces.

9.

Zoom into the area with a connector and see how the fixed point created from the weld has ensured the mesh seeding passes through the weld.


Step 4: Create connectors between the shell mesh for the front trusses and the reinforcement plate at pre-defined points. Perform the following steps to create and realize the connectors manually. 1.

On the toolbar, click on comp: and set the current component collector to Con_Truss_Plate.

2.

Go to the connectors module.

3.

Go to the spot panel.

4.

Go to the create sub-panel.

5.

For location:, select points.

6.

Select points >> by collector and select the component Con_Truss_Plate.

7.

Click select.

8.

Verify connect when: is set to now.

9.

For connect what:, select the following components: Front_Truss_1 Front_Truss_2 Reinf_Plate

10. Also for connect what:, toggle geom to elems. 11. Create connectors at the selected weld points. The connectors are organized into the current component collector Con_Truss_Plate.


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Step 5: Realize the connectors in the component Con_Truss_Plate into weld elements. 1.

Go to the realize sub-panel.

2.

Click connectors >> by collector and select Con_Truss_Plate.

3.

For type=, select weld.

4.

For tolerance =, type 5.

5.

Ensure the toggle is set to mesh dependent from mesh independent. When the option mesh dependent is active, if the realized finite element of the connector is coincident to a node of the shell mesh it is being connected to, the nodes are equivalenced. If there are no suitable nodes present, this option will partition the mesh accordingly to ensure the mesh seeding passes through the weld point.

6.

Realize the selected connectors into weld elements.

7.

Click return to go to the connectors module menu.


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Exercise 2: Weld Using a Master Connectors File and Duplicating and Reflecting Connectors. The purpose of this exercise is to become familiar with defining weld locations in HyperMesh by importing a master connector’s file. Also, become familiar with duplicating, reflecting, and updating connectors to create welds. In this exercise, you will first weld the two right rails to each other and to the two front trusses depicted in the image below. Do this as follows: 1) import weld point data from a master connectors file, 2) create connectors, and 3) realize the connectors into LS-DYNA 100 Mat100 (beam) welds.

Second, you will weld the two left rails to each other and to the two front trusses depicted in the image below. Do this as follows: 1) duplicate and reflect the connectors that were created by importing the master connectors file, 2) update the link information for the reflected connectors, and 3) realize the connectors into LS -DYNA 100 Mat100 (beam) welds.


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Third, you will combine adjacent 2T connectors into 3T connectors in order to update adjacent 2T welds to 3T welds.

Step 1: Load the LS-DYNA user profile. Step 2: Retrieve and view the model file frame_assembly_2.hm. Step 3: Create connectors to connect the right rails to each other and to the front trusses by importing a master connectors file. 1.

Enter the files

panel, import sub-panel.

2.

Activate the file type weld.

3.

Verify the weld option is set to connectors.

4.

Import the file rails_frt_truss.mwf. Notice the connectors are automatically created and are organized into the new component, CE_Locations.

5.


Step 4: Realize the connectors in the component, CE_Locations, into LSDYNA 100 Mat100 (beam) welds. 1.

On the toolbar, click on comp: and set the current component collector to CE_Locations.

2.

On the Setup menu, point to Connectors and click on Spot.

3.

Go to realize sub-panel.

4.

Select connectors >> by collector and select the component CE_Locations.

5.

For tolerance =, verify 5 is specified.

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6.

Realize the selected connectors into LS-DYNA 100 Mat100 (beam) welds.

7.


8.

On the toolbar, enter the display

9.

Notice the welds are organized into the following new component collectors:

panel.

C_^_1_7 C_^_6_7 C_^_2_7 C_^_1_6 where the naming convention for these components is C_^_[id of comp 1]_[id of comp 2].


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Step 5: Verify materials were automatically created when the LS-DYNA 100 Mat100 (beam) welds were created. 1.

On the Organize menu, click on Collectors.

2.


3.

Set the collector type to materials.

4.

Click name = and notice several materials (ids 8 through 11) were automatically created when the LS-DYNA 100 Mat100 (beam) welds were created. The naming convention for them is M_^_[id of comp 1]_[id of comp 2]. One material is created for every two components that are connected.

5.

Select any one of these materials.

6.

For card image =, notice it is set to MATL100 (*MAT_SPOTWELD).

7.

Click on info table. Notice values are automatically specified for the parameters’ density, Young’s Modulus, and Poisson’s Ratio.

8.

Close LsDyna material table.

9.


Step 6: Verify that properties were automatically created when the LS-DYNA 100 Mat100 (beam) welds were created. 1.

On the Setup menu, click on Card Editor.

2.

Set the collector type to props.

3.

Click name = and notice several properties (IDs 6 through 9) were automatically created when the LS-DYNA 100 Mat100 (beam) welds were created. The naming convention for them is P_^_[id of comp 1]_[id of comp 2]. One property is created for every two components that are connected.

4.

Select anyone of these properties.

5.

For card image =, notice it is set to SectBeam (*SECTION_BEAM).

6.

Edit the property. Notice that only default values are specified for the property’s parameters.

7.


Step 7: Verify that a contact was automatically created when the LS-DYNA 100 Mat100 (beam) welds were created. 1.

On the Setup menu, click on Interfaces.

2.

Go to card image sub-panel.

3.

For name =, select the automatically defined contact C_Spotweld_1.

4.

For card image =, notice it is set to ContactSpotweld (*CONTACT_SPOTWELD).

5.


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6.

Review the contact. Notice the contact’s master elements are temporarily colored blue while its slave elements are temporarily colored red.

7.


Step 8: Display the components Left_Rail_1 and Left_Rail_2 for elements. 1.

From the toolbar, enter the Display

panel.

2.

Display the components Left_Rail_1 and Left_Rail_2 for elements.

3.


Step 9: Duplicate the connectors created from the master connectors file and reflect them. 1.

Enter the collectors panel, create sub-panel.

2.

Set the collector type to components.

3.

For name = type CE_Locations_Dup.

4.

Create the component.

5.


6.

On the Tool page, enter the reflect panel.

7.

Switch the entity selector to connectors.

8.

Select connectors >> by collector and select the component CE_Locations.

9.

Select connectors >> duplicate >> current comp. The displayed connectors are duplicated and the duplicates are organized into the current component, CE_Locations_Dup.

10. Set the plane selector to x-axis. This is the axis normal to the plane of interest. 11. Click on base node

to reflect about.

12. Click x =. The fields for x =, y =, and z = are activated. By default their value is 0.000, which is the base point you want to reflect about. 13. Return to the reflect panel. 14. Reflect the connectors. 15. Return to the main menu.


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Step 10: Update the connectors for the left rails to link them to the left rail components. 1.

Enter the connectors module.

2.

Enter the add links panel.

3.

Click info table and select connectors >> by collector and select the component CE_Locations_Dup to open the Connector Information Table dialog.

4.

Notice in the Link1 and Link2 columns that the connectors have the links, comp Right_Rail_1 and comp Right_Rail_2. This data is from the master connectors file that you imported. These links need to be updated to reflect the two left rails.

5.

Click the select all icon

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to select all connectors in the table.


6.

For find what:, click in the Link:(ID) Name field. A HyperMesh panel menu appears that contains a component selector.

7.

Select the component Right_Rail_1.

8.

Click proceed to return to the dialog.

9.

For replace with:, click in the Link:(ID) Name field.

10. Select the component, Left_Rail_1, from the list. 11. Click proceed. 12. Update the connectors’ links. 13. Repeat steps 5 through 13, except find the Right_Rail_2 component and replace it with the Left_Rail_2 component. 14. Scroll through the list of connectors in the table to make sure none are linked to the right rail components. 15. Close the Connector Information Table. 16. Return to the connectors module menu.

Step 11: Verify that all connectors are realized and identify the pairs of adjacent connectors. 1.

Click info table and select connectors >> all, to review the connectors using the Connectors Information Table. Notice that the State column indicates that all of the connectors are realized.

2.

Close the Connectors Information Table.

3.

Click the reset icon

4.

Zoom into one of the two areas where the front trusses are connected to the rail components.

to clear the selection of connectors.

Notice that at these two areas, pairs of adjacent connectors exist.


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5.

From the toolbar, click on the Visualization icon

, and select the Connectors tab.

6.

Under color by, activate the option Layer.

7.

While still in the vis opts dialog, notice under layers that 2t (two thickness) is purple.

8.

Notice the connectors are now colored purple. This means each of these connectors links two components. Because the pairs of adjacent connectors create a series of two weld elements, you can combine each pair into a single connector, which links the three components together.

9.


Step 12: Isolate the pairs of adjacent, 2t connectors identified in the previous step. 1.

From the Display

2.

On the Tool page, enter the find panel, between sub-panel.

3.

Switch the entity type to find to connectors.

4.

Switch the entity selector to comps.

5.

Select the components Front_Truss_1 and Front_Truss_2.

6.

Find the connectors between these components.

7.

Reset

8.

Select the components Front_Truss_1 and Right_Rail_1.

9.

Find the connectors between these components.

10. Reset

panel, turn off all components for geometry.

the selection of components. .

the selection of components.

11. Select the components Front_Truss_1 and Left_Rail_1. 12. Find the connectors between these components. 13. Return to the main menu.

Step 13: Unrealize the displayed connectors. 1.

In the connectors module, enter the unrealize panel.

2.

Select connectors >> displayed.

3.

Unrealize the connectors. The weld elements associated to these connectors are deleted.

4.

Return to the connectors module menu.

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Step 14: Combine the pairs of adjacent, 2t connectors into 3t connectors. 1.

Enter the quality panel, connectors (unrealized) subpanel.

2.


3.

For tolerance = specify 5.

4.

Click preview combine. The header bar displays the message, "12 connector(s) found that need to be combined".

5.

Combine the connectors. The header bar displays the message, "6 connectors deleted". The connectors are now blue as this color is specified for 3t (three thickness) connectors in the Visualization dialog (accessed from the panel you are currently in).

6.


Step 15: Realize the 3t connectors into LS-DYNA 100 Mat100 (beam) welds and organize them into the component Con_Frt_Truss. 1.

From the header bar, click on comp: and set the current component to Con_Frt_Truss.

2.

From the Connectors module, go to spot panel, realize sub-panel.

3.


4.

For type =, select mat 100.

5.

For tolerance = verify 5 is specified.

6.

Realize the connectors.

7.



Exercise 3: Create Connectors from Existing Welds to Create New Welds of a Different Type The purpose of this exercise is to become familiar with absorbing existing finite element welds into connectors in order to create new finite element welds of a different type. In this exercise, LS-DYNA 101 Mat100 (hexa) welds already connect the rear trusses to each other. You will update the weld type to LS-DYNA 100 Mat100 (beam) welds. Do this as follows: 1) create connectors from the existing LS-DYNA 101 Mat100 (hexa) welds, and 2) realize the connectors into LS-DYNA 100 Mat100 (beam) welds.


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Step 1: Load the LS-DYNA user profile. Step 2: Retrieve and view the model file frame_assembly_3.hm. Step 3: Create connectors from existing LS-DYNA 101 Mat100 (hexa) welds. 1.

In the connectors module menu, enter the fe absorb panel. The Automated Connector Creation and FE Absorption dialog opens.

2.

Set FE Configs: to custom.

3.

Set FE Type: to dyna 101 mat 100 (hexa).

4.

Toggle Elem filter: from all to select.

5.

Click the Elem filter: Elements selector twice. A HyperMesh panel menu with an elems selector appears.

6.

Select elems >> by collector and then select the following components: C_^_6_11_HEX C_^_7_11_HEX C_^_8_11_HEX C_^_9_11_HEX C_^_10_11_HEX

7.

Click proceed to return to the dialog.

8.

Activate the Move connectors to FE component option.

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9.

Absorb the elements into connectors. Connectors are generated at the locations of the LS-DYNA 101Mat100 (hexa) welds. They are organized into the respective components to which the LS-DYNA 101 Mat100 (hexa) welds belong.

10. Close the dialog. 11. Return to the main menu.

Step 4: Isolate the 2t connectors between the Rear_Truss_2 component and the Right_Rail_2 and Left_Rail_2 components. 1.

From the Display

panel, turn off the display for all geometry components.

2.

On the Tool page, enter the find panel, between sub-panel.

3.

Switch the find entity type to connectors.

4.

Switch the entity selector to comps.

5.

Select the components Rear_Truss_2 and Right_Rail_2.

6.

Find the connectors between these components. Five connectors are found.

7.

Reset

the components selections.

8.

Select the components Rear_Truss_2 and Left_Rail_2.

9.

Find the connectors between these components. Five connectors are found.



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Step 5: Add Rear_Truss_1 as a third link to four of the ten displayed 2t connectors. 1.

In the connectors module menu, enter the add links panel.

2.

With the connectors selector active, select the four connectors indicated in the image below.

3.

For connect what: click comps and select the component Rear_Truss_1.

4.

Verify that the connect what: toggle is set to elems.

5.

Activate the search tol = option and specify 5 for it.

6.

Switch # of layers: to total 3.

7.

Click add links to update the connectors’ definitions. The connectors now appear blue as they are 3t connections.

8.


Step 6: Unrealize the connectors for the LS-DYNA 101 Mat100 (hexa) welds. 1.

From the Display

panel, display the geometry for only the following components:

C_^_6_11_HEX C_^_7_11_HEX C_^_8_11_HEX C_^_9_11_HEX C_^_10_11_HEX 2.

In the connectors module, enter the unrealize panel.

3.


4.

Unrealize the connectors. The weld elements associated to these connectors are deleted.

5.

From the toolbar, click on Visualization

6.

Under color by, activate state.

and select the Connectors tab.

Notice the displayed connectors are now colored yellow to indicate that they are not realized into FE elements. 7.


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Step 7: Realize the unrealized connectors into LS-DYNA 100 Mat100 (beam) welds. 1.

From the Connectors module, go to spot panel, realize sub-panel.

2.


3.

For type = select mat 100.

4.

For tolerance = verify that 5 is specified.

5.


6.



Exercise 4: Swap Welded Part The purpose of this exercise is to become familiar with swapping welded parts and updating their affected connections (welds). In this exercise, you will replace the component Rear_Truss_1 with a new, similar part and update its affected connections (welds). Do this as follows: 1) update the connectors to use the "use name" rule, 2) delete the old part, 3) import the new part, and 4) realize the corresponding connectors into LS-DYNA 100 Mat100 (beam) welds.

Step 1: Load the LS-DYNA user profile. Step 2: Retrieve and view the model file frame_assembly_4.hm.


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Step 3: Update the connectors to use the rule "use name" when reconnecting parts. 1.

Enter the connectors module menu.

2.

Enter the add links panel.

3.

Click info table and select connectors >> by collector and select the following components: C_^_6_11_HEX C_^_7_11_HEX C_^_8_11_HEX C_^_9_11_HEX C_^_10_11_HEX

4.

Click proceed to open the Connector Information Table dialog.

5.

Click on, Configure table

.

The Configure Table View dialog opens. 6.

Activate the Rule option.

7.

Close the Configure Table View dialog. Notice the rule is specified in the Link1, Link2, and Link3 columns. In this case, the rule is none for the selected connectors.

8.

Click the select all icon

to select all connectors in the table.

9.

For Find what:, change the Link:Rule to none.

10. For Replace with:, change the Link:Rule to use -name. 11. Update the connectors. 12. Close the Connectors Information Table. 13. From the toolbar, click on Visualization

and select Connectors tab

14. Under color by, select state and return to the main menu.

Step 4: Swap the component Rear_Truss_1 for a new version of it. 1.

Press F2 to go to the delete panel on the Tool page.

2.

Delete the component, Rear_Truss_1.

3.


4.

Press P on the keyboard to refresh the graphics area. Notice that the color of the displayed connectors changes from green (realized state) to yellow (unrealized state) for those connectors associated to the deleted component. This is because the deleted component was one of the connectors’ links.

5.

Notice the existing finite element welds are deleted.

6.

Enter the files panel / import sub-panel.

7.

Activate the file type option HM MODEL.

8.

Import the file rear_truss_1_new.hm.

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Step 5: Realize the unrealized connectors. 1.

In the connectors module menu, enter the spot panel, realize sub-panel.

2.


3.

For type =, select mat100.

4.

For tolerance = verify that 5 is specified.

5.


6.



Exercise 5: Troubleshoot Failure of Connectors to Realize The purpose for this exercise is to become familiar with troubleshooting the failure of connectors to realize. Specifically, this exercise will help you identify two common issues: 1) small projection tolerance and 2) missing link definitions. In this exercise, you will realize connectors to weld parts of a vehicle door frame. The model is depicted below.

Step 1: Load the LsDyna user profile. Step 2: Retrieve the HyperMesh file body_side_assembly.hm.


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Step 3: Realize all the connectors using a projection tolerance of 1.0 1.

In the connectors module menu, enter the spot panel, realize sub-panel.

2.

Select connectors >> all.

3.

For type =, select mat 100

4.

For tolerance =, specify 1.0

5.

Realize the selected connectors into LS-DYNA 100 Mat100 (beam) welds. Notice in the header message bar the message "257 connectors realized (9 failed)".

6.

Stay in the fe realize panel for the next step.

Step 4: Review the information table listing the connectors that failed to realize and determine the reasons for failure. 1.

From the toolbar, click the Visualization icon

and select Connectors tab.

A window appears. 2.

Under color by, deactivate Realized. The realized (green) connectors are turned off.

3.

Click info table and select connectors >> displayed . The Connector Information Table appears.

4.

Notice the following in the table for the five connectors with IDs 96, 155, 223, 261 and 262. In the Layers column, 2 layers are specified. In the Link1 and Link2 columns, a link is defined. Because the number of layers and links that were defined match, a possible cause for the connectors not realizing is a small projection tolerance.

5.

Notice the following in the table for the four connectors with IDs 152, 153, 154 and 156. In the Layers column, 3 layers are specified. In the Link1 column, a link is defined. In the Link2 column, no link is defined. There is no Link3 column with the third link definitions. Because the numbers of layers and links do not match, the likely cause for the connectors not realizing is undefined link definitions.

6.

Close the Connector Information Table.

7.

Stay in the spot panel, realize sub-panel for the next step.

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Step 5: Realize the failed connectors using a larger projection tolerance. 1.


2.

Verify that type = is mat 100.

3.

For tolerance =, specify 2.0.

4.

Realize the selected connectors into LS-DYNA 100 Mat100 (beam) welds. Notice in the header message bar the message "5 connectors realized (4 failed)".

5.


Step 6: Display only the failed connectors and the components they are supposed to link. 1.

In the toolbar, enter the Display

2.

Turn off all components for elements.

3.

Display the following components.

panel.

Comp1 (9) Comp2 (13) Comp10 (49) 4.

Return to the spot panel.

Step 7: Define the missing second link for the failed connectors. 1.

Click info table and select connectors >> displayed.

2.

At the bottom of the Connector Information Table, go to the AddLink tab.

3.

Deactive the option Increment layers by one.

4.

Click in the field under Link:(ID) Name. In the HyperMesh window, a menu panel with a component selector appears.

5.

Click component and select Comp2(13).

6.

In the Connector Information Table, click the select all button,

.

All the connectors in the table are selected. 7.

On the AddLink tab, click Add link.

8.

Answer Add Link to the pop-up question "Add specified link entity to the connector?". Notice a Link2 column appears and Comp2 (13) is the second link for all four connectors.

9.

Stay in the Connector Information Table for the next step.


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Step 8: Define the missing third link for the failed connectors. 1.

Click in the field under Link:(ID) Name.

2.

Click component and select Comp10 (49).

3.

Click on the select all button,

4.

On the AddLink tab, click Add link.

5.

Answer Add Link to the pop-up question "Add specified link entity to the connector?".

, to select all the connectors in the table

Notice a Link3 column appears and Comp10 (49) is the third link for all four connectors. 6.

Close the Connector Information Table.

7.


Step 9: Realize the failed connectors. 1.


2.

Verify that type = is mat 100.

3.

For tolerance =, specify 4.0.

4.

Realize the selected connectors into LS-DYNA 100 Mat100 (beam) welds.

5.

From toolbar, click on Visualization

6.

Under color by, select state and activate Realized.

and select Connectors tab.

Notice all the connectors appear and are colored green. All of them are realized into FE elements.


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LS-DYNA Solver Interface 8.0 Tutorials

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