2 building a model - · pdf filechapter 2: building a model 13 introduction to building a...

Chapter 2: Building A ModelPatran Interface to LS-DYNA Preference Guide

2 Building A Model

Introduction to Building a Model 12

Coordinate Frames 18

Finite Elements 19

Material Library 30

Element Properties 62

Loads and Boundary Conditions 91

Loads and Boundary Conditions Form 92

Load Cases 110

Patran Interface to LS-DYNA Preference GuideIntroduction to Building a Model

12

Introduction to Building a ModelThere are many aspects to building a finite element analysis model. In several cases, the forms used to create the finite element data are dependent on the selected analysis code and analysis type. Other parts of the model are created using standard forms.

Under Preferences on the Patran main form, is a selection for Analysis that defines the intended analysis code to be used for this model.

The analysis code may be changed at any time during model creation.This is especially useful if the model is to be used for different analyses, in different analysis codes. As much data as possible will be converted if the analysis code is changed after the modeling process has begun. The analysis option defines what will be presented to the user in several areas during the subsequent modeling steps.

These areas include the material and element libraries, including multi-point constraints, the applicable loads and boundary conditions, and the analysis forms. The selected Analysis Type may also affect the allowable selections in these same areas. For more details, see The Analysis Form (p. 8) in the Patran Reference Manual.

13Chapter 2: Building A ModelIntroduction to Building a Model

Table 2-1 summarizes the various LS-DYNA commands supported by the Patran LS-DYNA Preference.

Table 2-1 Supported LS-DYNA Entities

CATEGORY KEYWORD

BOUNDARY *BOUNDARY_SPC_SET*BOUNDARY_CYCLIC*BOUNDARY_PRESCRIBED_MOTION_SET*BOUNDARY_PRESCRIBED_MOTION_NODE

CONSTRAINED *CONSTRAINED_EXTRA_NODES_SET*CONSTRAINED_GENERALIZED_WELD *CONSTRAINED_GENERALIZED_BUTT*CONSTRAINED_GENERALIZED_FILLET*CONSTRAINED_GENERALIZED_SPOT*CONSTRAINED_JOINT_SPHERICAL*CONSTRAINED_JOINT_REVOLUTE*CONSTRAINED_JOINT_CYLINDRICAL*CONSTRAINED_JOINT_PLANAL*CONSTRAINED_JOINT_UNIVERSAL*CONSTRAINED_JOINT_TRANSLATIONAL*CONSTRAINED_LINEAR*CONSTRAINED_NODAL_RIGID_BODY *CONSTRAINED_NODAL_RIGID_BODY_INERTIA *CONSTRAINED_RIVET*CONSTRAINED_SHELL_TO_SOLID*CONSTRAINED_SPOTWELD*CONSTRAINED_TIE-BREAK*CONSTRAINED_TIED_NODES_FAILURE


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CONTACT *CONTACT_AUTOMATIC_ONE_WAY_SURFACE_TO_SURFACE*CONTACT_AUTOMATIC_SINGLE_SURFACE*CONTACT_AUTOMATIC_ SURFACE_TO_SURFACE*CONTACT_CONSTRAINT_NODES_TO_SURFACE*CONTACT_CONSTRAINT_SURFACE_TO_SURFACE*CONTACT_NODES_TO_SURFACE*CONTACT_ONE_WAY_SURFACE_TO_SURFACE*CONTACT_RIGID_BODY_ONE_WAY_TO_RIGID_BODY*CONTACT_RIGID_BODY_TWO_WAY_TO_RIGID_BODY*CONTACT_RIGID_NODES_TO_RIGID_BODY*CONTACT_SINGLE _SURFACE*CONTACT_SLIDNG_ONLY*CONTACT_SLIDING_ONLY_PENALTY*CONTACT_SURFACE_TO_SURFACE*CONTACT_TIEBREAK_NODES_TO_SURFACE*CONTACT_TIEBREAK_SURFACE_TO_SURFACE*CONTACT_TIED_NODES_TO_SURFACE*CONTACT_TIED_SURFACE_TO_SURFACE

CONTROL *CONTROL_BULK-VISCOSITY*CONTROL_CPU*CONTROL_CONTACT*CONTROL_COUPLING*CONTROL_DYNAMIC_RELAXATION*CONTROL_ENERGY*CONTROL_HOURGLASS*CONTROL_OUTPUT*CONTROL_SHELL*CONTROL_TERMINATION*CONTROL_TIMESTEP

DAMPING *DAMPING_GLOBAL*DAMPING_PART_MASS*DAMPING_PART_STIFFNESS

DATABASE *DATABASE_BINARY_D3PLOT*DATABASE_BINARY_D3THDT*DATABASE_BINARY_XTFILE*DATABASE_EXTENT_BINARY*DATABASE_HISTORY_NODE*DATABASE_HISTORY_BEAM*DATABASE_HISTORY_SHELL*DATABASE_HISTORY_SOLID*DATABASE_HISTORY_TSHELL


CATEGORY KEYWORD


DEFINE *DEFINE_COORDINATE_SYSTEM*DEFINE_CURVE*DEFINE_SD_ORIENTATION

ELEMENT *ELEMENT_BEAM *ELEMENT_DISCRETE*ELEMENT_MASS*ELEMENT_SHELL_THICKNESS*ELEMENT_SOLID_ORTHO*ELEMENT_TSHELL

INITIAL *INITIAL_MOMENTUM*INITIAL_VELOCITY*INITIAL_VELOCITY_NODE

LOAD *LOAD_BEAM_OPTION*LOAD_BODY_GENERALIZED*LOAD_NODE_OPTION*LOAD_SEGMENT*LOAD_SHELL _OPTION*LOAD_THERMAL_CONSTANT*LOAD_THERMAL_CONSTANT_NODE*LOAD_THERMAL_VARIABLE*LOAD_THERMAL_VARIABLE_NODE


CATEGORY KEYWORD


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MAT *MAT_ELASTIC_OPTION*MAT_PLASTIC_KINEMATIC*MAT_VISCOELASTIC*MAT_BLATZ-KO_RUBBER*MAT_ISOTROPIC_ELASTIC_PLASTIC*MAT_SOIL_AND_FOAM*MAT_JOHNSON_COOK*MAT_STRAIN_RATE_DEPENDENT_PLASTICITY*MAT_RIGID*MAT_COMPOSITE_DAMAGE*MAT_ENHANCED_COMPOSITE_DAMAGE*MAT_PIECEWISE_LINEAR_PLASTICITY*MAT_HONEYCOMB*MAT_MOONEY-RIVLIN_RUBBER*MAT_RESULTANT_PLASTICITY*MAT_CLOSED_FORM_SHELL_PLASTICITY*MAT_FRAZER_NASH_RUBBER_MODEL*MAT_LAMINATED_GLASS*MAT_LOW_DENSITY_FOAM*MAT_COMPOSITE_FAILURE_MODEL*MAT_VISCOUS_FOAM*MAT_CRUSHABLE_FOAM*MAT_RATE_SENSITIVE_POWERLAW_PLASTICITY*MAT_LINEAR_ELASTIC_DISCRETE_BEAM*MAT_NONLINEAR_ELASTIC_DISCRETE_BEAM*MAT_NONLINEAR_PLASTIC_DISCRETE_BEAM*MAT_SID_DAMPER_DISCRETE_BEAM*MAT_SPRING_ELASTIC*MAT_DAMPER_VISCOUS*MAT_SPRING_ELASTOPLASTIC*MAT_SPRING_NONLINEAR_ELASTIC*MAT_DAMPER_NONLINEAR_VISCOUS*MAT_SPRING_GENERAL_NONLINEAR*MAT_SPRING_MAXWELL*MAT_SPRING_INELASTIC*MAT_SOIL_AND_FOAM_FAILURE

NODE *NODE

PART *PART_OPTION

RIGIDWALL *RIGIDWALL_GEOMETRIC_SEVERAL OPTIONS

*RIGIDWALL_PLANAR_SEVERAL OPTIONS


CATEGORY KEYWORD


SECTION *SECTION_BEAM

*SECTION_DISCRETE

*SECTION_SHELL

*SECTION_SOLID_OPTION

*SECTION_TSHELL

SET *SET_NODE_OPTION

*SET_BEAM_OPTION

*SET_DISCRETE_OPTION

*SET_SEGMENT

*SET_SHELL_OPTION

*SET_SOLID_OPTION

*SET_TSHELL_OPTION

TITLE *TITLE


CATEGORY KEYWORD

Patran Interface to LS-DYNA Preference GuideCoordinate Frames

18

Coordinate FramesCoordinate frames will generate unique *DEFINE_COORDINATE_SYSTEM entries.

Only Coordinate Frames which are referenced by nodes, element properties, or loads and boundary conditions can be translated. For more information on creating coordinate frames see Creating Coordinate Frames (p. 393) in the Geometry Modeling - Reference Manual Part 2.

19Chapter 2: Building A ModelFinite Elements

Finite ElementsFinite Elements in Patran allows the definition of basic finite element construction. Created under Finite Elements are the nodes, element topology, and multi-point constraints.

For more information on how to create finite element meshes, see Mesh Seed and Mesh Forms (p. 25) in the Reference Manual - Part III.

Patran Interface to LS-DYNA Preference GuideFinite Elements

20

NodesNodes in Patran will generate unique *NODE entries. Nodes can be created either directly using the Node object, or indirectly using the Mesh object.


ElementsFinite Elements in Patran assigns element connectivity, such as Quad/4, for standard finite elements. The type of LS-DYNA element created is not determined until the element properties are assigned. See the Element Properties Form for details concerning the LS-DYNA element types. Elements can be created either directly using the Element object or indirectly using the Mesh object.


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Multi-Point ConstraintsMulti-point constraints (MPCs) can also be created from the Finite Elements menu. These elements define a rigorous behavior between several specified nodes. The forms for creating MPCs are found by selecting MPC as the Object on the Finite Elements form. The full functionality of the MPC forms are defined in Create Action (Mesh) (p. 11) in the Reference Manual - Part III.


MPC Types

To create an MPC, first select the type of MPC to be created from the option menu. The MPC types that appear in the option menu are dependent on the current settings of the Analysis Code and Analysis Type preferences. The following table describes the MPC types which are supported for LS-DYNA.

Note that the LS-DYNA definition of joints requires the definition of coincident pairs of nodes. Coincidence is not required of the Patran model. The mean position will be calculated during translation.

Note that some of the LS-DYNA *CONSTRAINED entries are supported as LBC’s rather than MPC’s. This is generally because they require more data than can be entered for an MPC or for the sake of consistency with other analysis preferences.

Degrees-of-Freedom

Whenever a list of degrees-of-freedom is expected for an MPC term, a listbox containing the valid degrees-of-freedom is displayed on the form. A degree-of-freedom is valid if:

1. It is valid for the current Analysis Code Preference.

2. It is valid for the current Analysis Type Preference.

3. It is valid for the selected MPC type.

MPC Type Analysis Type Description

Tied Shell to Solid Structural Defines a tie between a shell edge and solid elements.

Rivet Structural Defines pairs of nodes representing a rivet connection.

Cyclic

Symmetry

Structural Describes cyclic symmetry boundary conditions for a segment of the model.

Explicit Structural Creates a constraint equation between one degree of freedom of one node and selected degrees of freedom of other nodes.

Spherical Joint Structural Creates a spherical joint between two rigid bodies.

Revolute Joint Structural Creates a revolute joint between two rigid bodies.

Cylindrical Joint Structural Creates a cylindrical joint between two rigid bodies.

Planar Joint Structural Creates a planar joint between two rigid bodies.

Universal Joint Structural Creates a universal joint between two rigid bodies.

Translational Joint Structural Creates a translational joint between two rigid bodies.

Extra Nodes Structural Defines extra nodes for a rigid body. These are mainly used in conjunction with joint definition.


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In most cases, all degrees-of-freedom, which are valid for the current Analysis Code and Analysis Type Preferences, are valid for the MPC type. The following degrees-of-freedom are supported for the various analysis types:

Tied Shell to Solid

This subordinate MPC form appears when the Define Terms button is selected on the Finite Elements form, and the tied shell to solid type is selected. This form is used to create a *CONSTRAINED_SHELL_TO_SOLID entry. Note that a shell node may be tied to up to 9 brick nodes lying along a tangent vector to the nodal fiber. Nodes can move relative to each other in the fiber direction only.

Degree-of-freedom Analysis Type

UX Structural

UY Structural

UZ Structural

RX Structural

RY Structural

RZ Structural

Note: Care must be taken to make sure that a degree-of-freedom that is selected for an MPC actually exists at the nodes. For example, a node that is attached only to solid structural elements will not have any rotational degrees-of-freedom. However, Patran will allow you to select rotational degrees-of-freedom at this node when defining an MPC.


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Rivet

This subordinate MPC form appears when the Define Terms button is selected on the Finite Elements form, and the Rivet type is selected. This form is used to create one or more *CONSTRAINED_RIVET entries. Note that nodes connected by a rivet cannot be members of another constraint set that constrains the same degree of freedom, a tied interface, or a rigid body.


Explicit

This subordinate MPC form appears when the Define Terms button is selected on the Finite Elements form, and Explicit is the selected type. This form is used to create a *CONSTRAINED_LINEAR entry. This MPC type is used to define a linear constraint equation.


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Joint MPCs

This subordinate MPC form appears when the Define Terms button is selected on the Finite Elements form, and one of the joint types is selected. This form is used to create a *CONSTRAINED_JOINT_TRANSLATIONAL entry. The Relative Penalty Stiffness for this entry is defined on the main MPC form. The form will differ slightly for the 6 joint types. The spherical type requires only one dependent and one independent node. The translational joint requires 3 dependent and 3 independent nodes, and the other joint types require 2 dependent and 2 independent nodes.


Extra Nodes MPCs

This subordinate MPC form appears when the Define Terms button is selected on the Finite Elements form, and the Extra Nodes type is selected. This form is used to create a *CONSTRAINED_EXTRA_NODES_OPTION NODE/SET entry. This is the standard Rigid (Fixed) MPC type of Patran.

Patran Interface to LS-DYNA Preference GuideMaterial Library

30

Material LibraryThe Materials form will appear when the Material toggle, located on the Patran application selections, is chosen. The selections made on the Materials menu will determine which material form appears, and ultimately, which LS-DYNA material will be created.

The following pages give an introduction to the Materials form, and details of all the material property definitions supported by the Patran LS-DYNA preference.

Only material records which are referenced by an element property region or by a laminate lay-up will be translated. References to externally defined materials will result in special comments in the LS-DYNA input file, with material data copied from user identified files. This reference allows a user not only to insert material types that are not supported directly by the LS-DYNA preference, but also to make use of a standard library of materials.

31Chapter 2: Building A ModelMaterial Library

Materials FormThis form appears when Materials is selected on the main menu. The Materials form is used to provide options to create the various LS-DYNA materials.


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The following table outlines the options when Create is the selected Action.

Isotropic

Linear Elastic

This subordinate form appears when the Input Properties button is selected on the Materials form when Isotropic is the selected Object, and when Linear Elastic is the selected Constitutive Model on the Input Options form.

Object Option 1 Option 2

Isotropic • Linear Elastic • Linear Elastic (MAT 1)

• Elastoplastic • Plastic Kinematic (MAT 3)

• Iso. Elasto Plastic (MAT 12)

• Strain Rate Dependent (MAT 19)

• Piecewise Linear (MAT 24)

• Rate Sensitive (MAT 64)

• Resultant (MAT 28)

• Closed Form (MAT 30)

• Viscoelastic • Viscoelastic (MAT 6)

• Rigid • Material Type 20

• Johnson Cook • Material Type 15

• Rubber • Frazer Nash (MAT 31)

• Blatz-Ko (MAT 7)

• Mooney Rivlin (MAT 27)

• Foam • Soil and Foam (MAT 5/14)

• Viscous Foam (MAT 62)

• Crushable Foam (MAT 63)

• Low Density Urethane (MAT 57)

2D Orthotropic • Glass (laminated) • Laminate Glass (MAT 32)

3D Orthotropic • Honeycomb • Composite Honeycomb (MAT 26)

• Composite • Composite Damage (MAT 22)

• Composite Failure (MAT 59)

Composite • Laminate

Option 1 Option 2 Option 3

Linear Elastic Linear Elastic (MAT1) SolidFluid


Use this form to define the data for LS-DYNA Material Type 1 (*MAT_ELASTIC). If the “Material” is set as “Fluid” the parameters required are: Density, Bulk Modulus, Viscosity Coefficient, and Cavitation Pressure.

Elastoplastic

This subordinate form appears when the Input Properties button is selected on the Materials form, when Isotropic is the selected object, Elastoplastic is the selected Constitutive Model, and the following is the selected Implementation.

Option 1 Option 2

Elastoplastic Plastic Kinematic (MAT 3)


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Use this form to define the data for LS-DYNA Material Type 3 (*MAT_PLASTIC_KINEMATIC).

Elastoplastic


Option 1 Option 2

Elastoplastic Isotropic Elastic Plastic


Use this form to define the data for LS-DYNA Material Type 12 (*MAT_ISOTROPIC_ELASTIC_PLASTIC).


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Elastoplastic


Use this form to define the data for LS-DYNA Material Type 19 (*MAT_STRAIN_RATE_DEPENDENT_PLASTICITY).

Option 1 Option 2

Elastoplastic Strain Rate Dependent Plasticity


Elastoplastic

This subordinate form appears when the Input Properties button is selected on the Materials form, when Isotropic is the selected object, and one of the following combinations is selected.

Use the form on the next page to define the data for LS-DYNA Material Type 24 (*MAT_PIECEWISE_LINEAR_PLASTICITY). The contents of the form will vary depending upon which option is selected. If the bilinear option is selected then the tangent modulus is required. The linearized option requires definition of a strain dependent field. If the General rate model is selected instead of the Cowper Symonds model then the Yield Stress is defined as a strain rate dependent field.

Option 1 Option 2 Option 3 Option 4

Elastoplastic Piecewise Linear Plasticity Bilinear Cowper Symonds Rate ModelGeneral Rate Model

Linearized Cowper Symonds Rate ModelGeneral Rate Model


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Elastoplastic


Use this form to define the data for LS-DYNA Material Type 64 (*MAT_RATE_SENSITIVE_POWERLAW_PLASTICITY).

Option 1 Option 2

Elastoplastic Rate Sensitive Power Law


40

Elastoplastic


Use this form to define the data for LS-DYNA Material Type 28 (*MAT_RESULTANT_PLASTICITY).

Option 1 Option 2

Elastoplastic Resultant


Elastoplastic


Option 1 Option 2

Elastoplastic Closed Form Shell


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Use this form to define the data for LS-DYNA Material Type 30 (*MAT_CLOSED_FORM_SHELL_PLASTICITY).


Viscoelastic

This subordinate form appears when the Input Properties button is selected on the Materials form, Isotropic is the selected Object, and the Viscoelastic Constitutive model is selected. Use this form to define the data for LS-DYNA Material Type 6 (*MAT_VISCOELASTIC).


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Rigid

This subordinate form appears when the Input Properties button is selected on the Materials form, Isotropic is the selected Object, and the Rigid Constitutive model is selected. Use this form to define the data for LS-DYNA Material Type 20 (*MAT_RIGID).


Johnson Cook

This subordinate form appears when the Input Properties button is selected on the Materials form, Isotropic is the selected Object, and one of the following combinations is selected.


Johnson Cook Material Type 15 No Iterations Minimum PressureNo tension, Minimum StressNo tension, Minimum Pressure

Accurate Minimum PressureNo tension, Minimum StressNo tension, Minimum Pressure


46

Use the form on the next page to define the data for LS-DYNA Material Type 15 (*MAT_JOHNSON_COOK). The contents of the form do not vary.

Additional data for this form are: Effective Plastic Strain rate, Specific Heat, Failure Stress/Pressure, and 5 Failure Parameters.


Rubber

This subordinate form appears when the Input Properties button is selected on the Materials form, Isotropic is the selected Object, Rubber is the selected Constitutive Model, and the following is the selected Implementation.

Use this form to define the data for LS-DYNA Material Type 7 (*MAT_BLATZ-KO_RUBBER).

Option 1 Option 2

Rubber Blatz-Ko


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Rubber

This subordinate form appears when the Input Properties button is selected on the Materials form, Isotropic is the selected Object, Rubber is the selected Constitutive Model, and the following is the selected Implementation.

Use this form to define the data for LS-DYNA Material Type 27 (*MAT_MOONEY_RIVLIN_RUBBER).


Rubber Mooney Rivlin CoefficientsLeast Square


Rubber

This subordinate form appears when the Input Properties button is selected on the Materials form, Isotropic is the selected Object, Rubber is the selected Constitutive Model, and one of the following combinations is selected.

Use the form on the next page to define the data for LS-DYNA Material Type 31 (*MAT_FRAZER_NASH_RUBBER_MODEL). The contents of the form varies depending on the option selected for defining the material response. If the model is defined as least squares fit then specimen data and a field defining force versus change in gauge length are required instead of the coefficients that appear on the form below. Note that a strain field must be defined, although this is interpreted by the translator as force versus actual change in the gauge length. If the strain limits are to be ignored then maximum and minimum strain limits are not required.


Rubber Frazer-Nash Coefficients RespectIgnore

Least Squares Fit RespectIgnore


50


Foam

This subordinate form appears when the Input Properties button is selected on the Materials form, Isotropic is the selected Object, Foam is the selected Constitutive Model, and one of the following combinations is selected.

Use the form on the next page to define the data for LS-DYNA Material Type 57 (*MAT_LOW_DENSITY_FOAM). The contents of the form does not vary.


Foam Low Density Urethane Bulk Viscosity Inactive No TensionMaintain Tension

Bulk Viscosity Active No TensionMaintain Tension


52


Foam

This subordinate form appears when the Input Properties button is selected on the Materials form, Isotropic is the selected Object, Foam is the selected Constitutive Model, and the following is the selected Implementation.

Use this form to define the data for LS-DYNA Material Type 62 (*MAT_VISCOUS_FOAM).

Option 1 Option 2

Foam Viscous Foam


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Foam

This subordinate form appears when the Input Properties button is selected on the Materials form, Isotropic is the selected Object, Foam is the selected Constitutive Model, and the following is the selected Implementation.

Use this form to define the data for LS-DYNA Material Type 63 (*MAT_CRUSHABLE_FOAM).

Option 1 Option 2

Foam Crushable


Foam

This subordinate form appears when the Input Properties button is selected on the Materials form, Isotropic is the selected Object, Foam is the selected Constitutive Model, and one of the following combinations is selected.

Use the form on the next page to define the data for LS-DYNA Material Type 5 (*MAT_SOIL_AND_FOAM) or Material Type 14 (*MAT_SOIL_AND_FOAM_FAILURE). Choice between the Type 5 and Type 14 is solely on the basis of whether failure is permitted when pressure meets the failure pressure.


Foam Soil and Foam InactiveInactiveActiveActive

Allow CrushingReversibleAllow CrushingReversible


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2D Orthotropic

Laminated Glass

This subordinate form appears when the Input Properties button is selected on the Materials form, 2D Orthotropic is the Selected Object, and when Laminated Glass is the selected Constitutive Model on the Input Options form. Use this form to define the data for LS-DYNA Material Type 32 (*MAT_LAMINATED_GLASS).


3D Orthotropic

Honeycomb

This subordinate form appears when the Input Properties button is selected on the Materials form when 3D Orthotropic is selected on the Material form, and when the Honeycomb Constitutive model is


58

selected. Use this form to define the data for LS-DYNA Material Type 26 (*MAT_HONEYCOMB).


Composite

This subordinate form appears when the Input Properties button is selected on the Materials form when 3D Orthotropic is the selected Object, Composite is the Selected Constitutive Model, and the following is the selected Implementation.

Use the subordinate form on the following page to define the data for LS-DYNA Material Type 22 (*MAT_COMPOSITE_DAMAGE).

Option 1 Option 2

Composite Damage


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Composite Failure

This subordinate form appears when the Input Properties button is selected on the Materials form, 3D Orthotropic is the selected Object, Composite is the Selected Constitutive Model, and the following is the selected Implementation.


Composite Failure EllipsoidalFaceted


Use the subordinate form on the following page to define the data for LS-DYNA Material Type 58 (*MAT_COMPOSITE_FAILURE_MODEL).

Patran Interface to LS-DYNA Preference GuideElement Properties

62

Element PropertiesThe Element Properties form appears when the Properties toggle, located on the Patran main form, is chosen.There are several option menus available when creating element properties. The selections made on the Element Properties menu will determine which element property form appears, and ultimately, which LS-DYNA element will be created.

The following pages give an introduction to the Element Properties form, and details of all the element property definitions supported by the Patran LS-DYNA Preference.

Element Properties FormThis form appears when Properties is selected on the main menu. There are four option menus on this form, each will determine which LS-DYNA element type will be created and which property forms will appear. The individual property forms are documented later in this section. For a full description of this form, see Element Properties Forms (p. 67) in the Patran Reference Manual.

63Chapter 2: Building A ModelElement Properties


64

The following table outlines the option menus when Analysis Type is set to Structural.

Object Type Option 1 Option 2

0D • Mass

• Grounded Spring LinearNon-LinearElastoplasticGeneral Non-LinearViscoelasticInelastic

• Grounded Damper Linear Non-Linear

1D • Beam General SectionDimensioned Section

• Rod

• Spring Linear ScalarFollower

Non-linear ScalarFollower

Elastoplastic ScalarFollower

General Non-Linear ScalarFollower

Viscoelastic ScalarFollower

Inelastic ScalarFollower

• Damper Linear ScalarFollower

Non-Linear ScalarFollower

Side Impact

• Discrete beam LinearNon-LinearNon-Linear Plastic

• Weld Spot StandardGeneral

• Fillet


Mass

This subordinate form appears when the Input Properties button is selected on the Element Properties form when the following options are chosen.

• Butt

• Integrated Beam Rectangular Hughes LiuBelytschko Schwer

Tubular Hughes LiuBelytschko Schwer

• Part Inertia 1D General SectionDimensioned Beam

2D • Shell Homogeneous Hughes LiuBelytschko TsayBCIZ Tri ShellCo TriS/R Hughes LiuS/R Co-rotationalBelytschko LevialthanBely Wong ChiangFast Hughes Liu

Laminate Hughes LiuS/R Hughes LiuFast Hughes LiuDefault

• Membrane Bely T MembraneFully Integrated

• Part Inertia 2D

3D • Solid Constant StressS/R 8 NodeQuadratic 8 NodeS/R Tetrahedron

• Thick Shell 1 Point2 x 2 point

• Part Inertia 3D

Action Dimension Type Topologies

Create 0D Mass Point

Object Type Option 1 Option 2


66

Use this form to create an *ELEMENT_MASS entry. This defines a lumped mass element of the structural model.

Grounded Spring


Use this form to create a *ELEMENT_DISCRETE entry and one of the *MAT_SPRING_type and *SECTION_DISCRETE data entries. This defines a scalar spring element of the structural model. Only one node is used in this method. The other node is defined to be grounded. The data on this form will vary upon the spring type.

Action Dimension Type Option(s) Topologies

Create 0D Grounded Spring Linear, Non-Linear, Elastoplastic, General Non-Linear, Viscoelastic, Inelastic

Point/1


Grounded Damper


Use this form to create an *ELEMENT_DISCRETE entry and one of the *MAT_DAMPER_type and *SECTION_DISCRETE data entries. This defines a scalar damper element of the structural model. Only one node is used in this method. The other node is defined to be grounded.The data on this form will vary upon the damper type.


Create 0D Grounded Damper Linear/Non-Linear Point/1


68

Beam (General Section)


Use this form to create an *ELEMENT_BEAM entry together with its associated *SECTION_BEAM and *INTEGRATION_BEAM data entry. This defines a simple beam element of the structural model.

Action Dimension Type Option(s) Option 2 Topologies

Create 1D Beam General Section Bar/2


This is a list of Input Properties, available for creating a resultant beam that were not shown on the previous page. Use the menu scroll bar on the input properties form to view these properties.

Beam (Dimensioned Section - Hughes-Liu)


Property Name Description

Axial Damping Defines the axial damping factor. This property is optional.

Mass Damping Defines the mass damping factor. This property is optional.

Stiffness Damping Defines the stiffness damping factor. This property is optional.

Bending Damping Defines the bending damping factor. This property is optional.


Create 1D Beam Dimensioned Section Hughes -Liu Bar/2


70







Beam (Dimensioned Section - Belytschko-Schwer)




Create 1D Beam Dimensioned Section Belytschko Schwer Bar/2


72


Rod


Use this form to create *ELEMENT_BEAM and *SECTION_BEAM data entries. This defines a tension-compression-torsion element of the structural model.


Axial Damping Defines the axial damping factor. This property is optional.



Bending Damping Defines the bending damping factor. This property is optional.


Create 1D Rod Bar/2


Scalar Spring


Use this form to create an *ELEMENT_DISCRETE entry and one of the *MAT_SPRING_type and *SECTION_DISCRETE data entries. This defines a scalar spring element of the structural model. The data on this form will vary upon the spring type. Additional parameters are available to define the dynamic values based on static data.

Action Dimension Type Option 1 Option 2 Topologies

Create 1D Spring Linear, Non-Linear, Elastopastic,General Non-Linear, Viscoelastic,Inelastic

Scalar, Bar/2


74

Scalar Damper



Create 1D Damper Linear, Non-Linear Scalar Bar/2


Use this form to create an *ELEMENT_DISCRETE entry and one of the *MAT_DAMPER_type and *SECTION_DISCRETE data entries. This defines a scalar damper element of the structural model. The data on this form will vary upon the damper type.

Follower Damper



Create 1D Damper Linear, Non-Linear Follower Bar/2


76

Use this form to create an *ELEMENT_DISCRETE entry and one of the *MAT_DAMPER_type and *SECTION_DISCRETE data entries. This defines a follower damper element of the structural model. The data on this form will vary upon the damper type.

Side Impact Damper


Use this form to create an *ELEMENT_BEAM entry and *MAT_SID_DAMPER_DISCRETE_BEAM and *SECTION_BEAM data entries. This defines a side impact damper element of the structural model. Additional properties required to fully define the damper behavior are input by scrolling down the form.

Action Dimension Type Option Topologies

Create 1D Damper Side Impact Bar/2


Discrete Beam


Use this form to create an *ELEMENT_BEAM entry together with its associated *MAT_type_DISCRETE_BEAM and *SECTION_BEAM data entries. This defines a simple beam element of the structural model. The data on this form will vary upon the beam type.


Create 1D Discrete Beam Linear, Non-Linear, Non-Linear Plastic Bar/2


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Spot Weld


Use this form to create a *CONSTRAINED_SPOTWELD or *CONSTRAINED_GENERALIZED_WELD_SPOT entry. This defines a spot weld connecting two nodes of the model. The data on this form will vary upon the weld type.


Create 1D Weld Spot Standard/General Bar/2


Fillet Weld


Use this form to create a *CONSTRAINED_GENERALIZED_WELD_FILLET entry. This defines a fillet weld between two parts of the model.


Create 1D Weld Fillet Bar/2


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This is a list of Input Properties available for creating a Fillet Weld that were not shown on the previous page. Use the scroll bar on the Input properties form to view these properties.


Width of Flange, w Define width of flange. This property is required.

Width of Weld, a Define width of fillet weld. This property is required.

Weld Angle, Alpha Define the weld angel, Alpha. This property is required.


Butt Weld


Use this form to create a *CONSTRAINED_GENERALIZED_WELD_BUTT entry. This defines a butt weld between two parts of the model.


Create 1D Weld Butt Bar/2


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Integrated Beam


Use this form to create an *ELEMENT_BEAM together with its associated *SECTION_BEAM and *INTEGRATION_BEAM data entries. This defines a simple beam element of the structural model. The data entry will vary upon the formulation option.


Create 1D Integrated Beam Rectangular, Tubular

Belytschko Schwer, Hughes -Liu

Bar/2


Part Inertia 1D




Create 1D Part Inertia 1D Bar/2


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Shell


Use this form to create an *ELEMENT_SHELL_OPTION entry together with the associated *SECTION_SHELL entry. The data varies upon the type of element formulation.

Action Dimension Type Option Formulation Topologies

Create 2D Shell Homogeneous Hughes Liu, Belytschko-Tsay, BCIZ Tri Shell, Co-Tri, S/R Hughes Lui, S/R Co_rotational, Belytschko Levialthan, Bely Wong Chiang, Fast Hughes Liu.

Tri/3, Quad/4

Laminate Hughes Liu, S/R Hughes Liu, Fast Hughes Liu, Default.


Membrane


Use this form to create an *ELEMENT_SHELL_OPTION entry together with the associated *SECTION_SHELL entry.


Create 2D Membrane Bely T Membrane, Fully Integrated

Tria/3, Quad/4


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Part Inertia 2D






Solid


Use this form to create an *ELEMENT_SOLID entry together with the associated *SECTION_SOLID entry.

Action Dimension Type Option 1 Topologies

Create 3D Solid Constant Stress, S/R 8 Node, Quadratic 8 Node, S/R Tetrahedron

Hex/8


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Thick Shell


Use this form to create an *ELEMENT_TSHELL entry together with the associated *SECTION_TSHELL entry.

Action Dimension Type Option 1 Topologies

Create 3D Thick Shell 1 Point2x2 Point

Hex/8


Part Inertia 3D


Note: The correct node numbering is essential for correct use. To ensure proper orientation, extreme care must be used in defining the connectivity. (See the LS-DYNA User’s Manual for further details.)




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91Chapter 2: Building A ModelLoads and Boundary Conditions

Loads and Boundary ConditionsThe Loads and Boundary Conditions form will appear when the Loads/BCs toggle, located on the Patran application selections, is chosen. When creating a loads and boundary conditions there are several option menus. The selections made on the Loads and Boundary Conditions menu will determine which loads and boundary conditions form appears, and ultimately, which LS-DYNA loads and boundary conditions will be created.

The following pages give an introduction to the Loads and Boundary Conditions form, and details of all the loads and boundary conditions supported by the Patran LS-DYNA Analysis Preference.

Patran Interface to LS-DYNA Preference GuideLoads and Boundary Conditions Form

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Loads and Boundary Conditions FormThis form appears when Loads/BCs is selected on the main form. The Loads and Boundary Conditions form is used to provide options to create the various LS-DYNA loads and boundary conditions. For a definition of full functionality, see Loads and Boundary Conditions Form (p. 21) in the Patran Reference Manual.

93Chapter 2: Building A ModelLoads and Boundary Conditions Form

The following table outlines the options when Create is the selected action.

Static (Not Time Varying)

This subordinate form appears when the Input Data button is selected on the Loads and Boundary Conditions form when the Current Load Case Type is Static. The Current Load Case Type is set on the Load Case form, for more information see Loads and Boundary Conditions Form. The information on the Input Data form will vary depending on the selected Object. Defined below is the standard information found on this form. Note that this form is not used with the LS-DYNA Preference.

Object Type

Displacement Nodal

Force Nodal

Pressure Element Uniform

Temperature Nodal

Initial Velocity Nodal

Velocity Nodal

Acceleration Nodal

Initial Momentum Element Uniform

Contact Element Uniform

Geometric Rigid Wall Nodal

Planar Rigid Wall Nodal

Tied Shells Element Uniform

Tied Shell Edges Element Uniform

Nodal Rigid Body Nodal

Nodal Inertial Load Nodal


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Transient (Time Varying)

This subordinate form appears when the Input Data button is selected on the Loads and Boundary Condition form when the Current Load Case Type is Time Dependent. The Current Load Case Type is set on the Load Case form, for more information see Loads and Boundary Conditions Form and Load Cases. The information on the Input Data form will vary, depending on the selected Object. Defined below is the standard information found on this form.


Contact Toolkit

Introduction

This section describes the user interface provided by Patran to access the contact features of explicit dynamics finite element codes. This interface is used during definition of the Contact LBC types: Self Contact, Master/Slave Surface, Master/Slave Node, and Subsurface.


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Tools have been provided to enable the user to quickly and easily define contact conditions. Specification of contact is conceptually simple, involving either one or two contact surfaces, and a set of contact parameters which control the interaction of the surfaces.

Contact Types

A contact condition in which a single logical surface may come into contact only with itself is described as self-contact, and requires the specification of a single Application Region. A contact condition in which two logical surfaces may contact each other is described as Master/Slave contact, and requires specification of two Application Regions. Master/Slave contact is further subdivided by the definition of Master/Slave Surface and Master/Slave Node. Master/Slave Surface describes the condition in which both the master and slave surfaces are described using element faces, whereas Master/Slave Node describes the condition in which the Slave surface is described using only nodes.

Contact Construction

Tools are provided to enable the construction of contact surfaces, using the standard Patran select tool mechanisms (2D elements, 3D element faces), or groups. Contact subsurfaces can also be constructed using these tools, and later used to define a complete logical contact surface. This functionality allows the user to use the select tool to specify application regions on Patran geometry or the associated FEM entities or to define a more complex contact surface that is assembled from a mixture of 2D and 3D element faces, and to simply combine groups of 2D elements taking into account the direction of the contact outward normal. (For 2D elements, the outward normal can be reversed for contact purposes without modifying the underlying element topology.) Use of the group select mechanism is restricted to FEM entities only. Visualization of the specified contact condition is provided by graphically previewing but is not currently supported for geometry entities.

“Simple” contact surfaces include surfaces which may be described entirely by the faces of 3D elements, or by 2D elements whose outward normals are aligned with the desired contact normal direction. These contact surfaces may be constructed entirely using a single select mechanism (either Select Tool or Group method). Simple contact surfaces may not include a mixture of 3D element faces and 2D elements, or 2D elements whose outward normals are not all aligned with the desired contact normal direction.

“Complex” contact surfaces are defined as those surfaces which consist of a mixture of 2D elements and 3D element faces, or all 2D elements but with some of the outward normal incorrectly aligned. Contact conditions which include complex contact surfaces must be constructed using “Subsurfaces,” where each subsurfaces is a “Simple” contact surface. Definition of contact surfaces is limited to one method; i.e., it is not permissible to mix “Select Tool,” “Group,” or “Subsurface” within the definition of a contact surface.

The following section describes how each of the contact surface creation methods is used to describe a simple contact surface.

Use of the Select Tool

The select tool is use to graphically select the desired entities from the model. When this method is selected, the user must specify which dimensionality the intended object has, i.e. 3D, 2D or Nodal. If the selected dimensionality is 2D, then the user can further specify whether the top, bottom or both surfaces


are required. Selection of top will result in a contact surface whose outward normal is coincident with the element outward, whereas selection of bottom will result in a contact surface whose outward normal is in the opposite direction to the element outward normal. The user can toggle between Top, Bottom or Both at any time during selection, however all of the selected entities will be assigned the same logical direction. Selection of 3D allows the user to select either all or all free faces of 3D elements. No user specification of the contact normal direction is required for 3D elements since the program automatically specifies this direction. No contact direction is applicable to Nodal contact surfaces.

It is not permissible to mix 3D, 2D and Nodal entities within a single Application Region. (This functionality is provided through the use of contact subsurfaces). The select tool can be used to select on the basis of either FEM or Geometry entities.

Use of the Group Tool

The Group tool is used to define simple contact surfaces on the basis of Patran group names. When this method is selected, the user must specify which dimensionality the intended object has, i.e. either 3D, 2D or Nodal. The entities which will be selected for use in the contact surface in this case are either all 3D free surfaces in the group, all 2D elements or all nodes contained in the selected group. In the case of 2D elements, the user may specify whether the contact normal direction is coincident with the element top, bottom or both faces. Multiple groups may be selected. However, it should be noted that both the selected element dimensionality and contact normal direction apply across all selected groups.

Use of the Subsurface Tool

Contact Subsurfaces may be defined using either of the above methods. Subsurfaces may then be used in the specification of Master, Slave or Self contact surfaces. When this option is used, the user may not specify element dimensionality or contact normal direction since this information has already been defined during subsurface definition. As many sub-surfaces as required may be selected to form the desired complex contact subsurface.

Contact: Application Region

This form is used to define contact surfaces. The form will vary depending upon which options are selected, however two basic configurations are used depending on whether the contact condition requires specification of a single contact surface or two contact surfaces.


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Single Application Region

The following form is used to define a single surface contact or a subsurface.


Dual Application Region

The following form is used to define either of the master-slave contact types.


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Contact: Input Data

The Input Data form is used to specify parameters which control the behavior of the contact condition. The contents of the form will vary depending upon which option is selected. No Input Data is required for the Subsurface option since subsurfaces do not constitute a contact condition on their own.

Object TablesThere are areas on the static and transient input data forms where the load data values are defined. The data fields which appear depend on the selected load Object and Type. In some cases, the data fields also depend on the selected Target Element Type. The following Object Tables outline and define the various input data that pertains to a specific selected object:


Displacement

If the displacement/rotational component is zero, it will result in generation of a *BOUNDARY_SPC_OPTION NODE/SET entry, which defines translational and rotational constraints in the prescribed coordinate system. If the values are non-zero then this will result in generation of a *BOUNDARY_PRESCRIBED_MOTION_OPTION NODE/SET entry.

Force

This defines a *LOAD_NODE_OPTION POINT/SET entry. For transient load cases an auxiliary *DEFINE_CURVE entry is defined from the time dependent field selected.

Pressure

Creates a *LOAD_SHELL_OPTION ELEMENT/SET entry depending upon whether one or more shell elements are selected.

Object Type Analysis Type

Displacement Nodal Structural

Input Data Description

Translations (T1,T2,T3) Defines the enforced translational displacement values in the specified coordinate system. These are in model length units.

Rotations (R1,R2,R3) Defines the enforced rotational displacement values in the specified coordinate system. These are in degrees.


Force Nodal Structural


Force (F1,F2,F3) Defines the applied forces in the translation degrees-of-freedom in the specified coordinate system.

Moment (M1,M2,M3)

Defines the applied moments in the rotational degrees-of-freedom in the specified coordinate system.

Object Type Analysis Type Dimension

Pressure Element Uniform Structural 2D


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Creates a *LOAD_SEGMENT.

Temperature

When the load case type is static this creates a *LOAD_THERMAL_CONSTANT or a *LOAD_THERMAL_CONSTANT_NODE entry depending upon the application region. When the load case type is transient this creates a *LOAD_THERMAL_VARIABLE or a *LOAD_THERMAL_VARIABLE_NODE entry depending upon the application region.

Initial Velocity


Top Surf Pressure Defines the top surface pressure load on shell elements.

Bot Surf Pressure Defines the bottom surface pressure load on shell elements.

Edge Pressure Defines the edge pressure load on shell elements.


Pressure Element Uniform Structural 3D


Pressure Defines the face pressure value on solid elements. If a spacial field is referenced, it will be evaluated once at the center of the applied region.


Temperature Nodal Structural


Temperature Defines the temperature which will be constant if the load case is static or scaled by the load curve if the load curve is transient.


Initial Velocity Nodal Structural


Creates a *INITIAL_VELOCITY or *INITIAL_VELOCITY_NODE entry (The latter when there is only a single node). The exempted node option is not supported for the former entry as Patran provides more natural methods of defining nodal sets. Note that is an Analysis coordinate frame is specified the values are transformed into the global coordinates system.

Velocity

If the load case type is transient this will result in generation of a *BOUNDARY_PRESCRIBED_MOTION_OPTION NODE/SET entry. There is no corresponding data for static load cases.

Acceleration

If the load case type is transient this will result in generation of a *BOUNDARY_PRESCRIBED_MOTION_OPTION NODE/SET entry. There is no corresponding data for static load cases.


Trans Veloc (v1,v2,v3) Defines the Velocity fields for translational degrees-of-freedom.

Rot Veloc (w1,w2,w3) Defines the Velocity fields for rotational degrees-of-freedom.


Velocity Nodal Structural


Trans Veloc(v1,v2,v3) Defines the enforced translational velocity values in the specified coordinate system. These are in model length units per unit time.

Rot Veloc (w1,w2,w3) Defines the enforced rotational velocity values in the specified coordinate system. These are in degrees per unit time.


Acceleration Nodal Structural


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Initial Momentum

Creates a *INITIAL_MOMENTUM entry. Note that global coordinates apply only. This applies only for solid elements.

Contact

Four types of contact exist. Three of these are complete definitions and have associated input data. The fourth is the subsurface type which is used to define part of a contacting surface.


Trans Accel (A1,A2,A3) Defines the enforced translational acceleration values in the specified coordinate system. These are in model length units per unit time squared.

Rot Accel (a1,a2,a3) Defines the enforced rotational acceleration values in the specified coordinate system. These are in degrees per unit time squared.


Initial Momentum Element Uniform Structural 3D


Momentum (m1,m2,m3) Defines the Velocity fields for translational degrees-of-freedom.

Deposition Time Time at which energy is deposited in solid elements.

Object Type Option 1

Contact Element Uniform Self ContactSubsurfaceMaster-Slave SrrfaceMaster-Slave Node


The contact options for each of the contact types are defined in the following table.

Input Data OptionSelf

Contact

Master Slave

Surface

Master Slave Node

Contact Type Single Surface (4) x

Surface to Surface (3) x

One-way Surface to Surface(10) x

Tied surface to Surface (2) x

Tie break Surface to Surface(9) x

Sliding Only (1) x

Sliding Only Penalty (p1) x

Rigid Body One way(21) x

Rigid body Two way(19) x

Nodes to Surface (5) x

Tied nodes to Surface (6) x

Tie break Nodes to Surface (8) x

Rigid Nodes to Body(20) x

Contact Method Automatic x x x

Standard x x x

Constrain x x

Constraint(Only available when Contact Method = Constrain)

Fully Symmetric x x

Constrain to Slave x x

Constrain to Master x x

Thickness definition Define x x x

Scale x x x

Surface Behavior Penalty x x x

Soft-Constraint x x x

Small penetration check

On x x x

Off x x x

Diagonal x x x

Interface output None x x x

Slave x x x

Master x x

Both x x


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The contact input parameters are defined in the following table.

Geometric Rigid Wall

Four types of geometric rigid wall exist:

1. Flat

2. Prismatic

3. Cylindrical

4. Spherical

The options are as follows:

1. Motion: Static/Defined Velocity/Defined Displacement

2. Friction: Frictionless/No Slip/Frictional

Input Data Self ContactMaster Slave

SurfaceMaster Slave

Node

Static Friction Coefficient x x x

Dynamic Friction Coefficient x x x

Exponential Decay Coefficient x x x

Viscous Friction Coefficient x x x

Viscous Damping Coefficient x x x

Birth Time x x x

Death Time x x x

Scale Factor on Slave Stiffness x x x

Scale Factor on Master Stiffness x x

Master Surface Thickness x x

Slave Thickness Scale Factor x x x

Scale Factor to Constraint Forces x x x

Max. Param Coord in Search x x x

Cycles between Bucket Sorts x x x

Cycle between Force Updates

Maximum Penetration x


Planar Rigid Wall Nodal Structural


The input data for geometric rigid walls are as follows:

Note that the user must select a local coordinate system that is used when generating the geometry of the wall. The local z axis is always the n axis in the LS-DYNA definition. The velocity is defined as a time field in the local z direction.

Planar Rigid Wall

Two types of planar rigid wall exist:

1. Finite

2. Infinite

The options are as follows:

1. Motion: Static/Moving

2. Friction: No Slip/Frictionless/Isotropic Frictional/Orthotropic Frictional

Note that the orthotropic frictional behavior is available only for a static rigid wall.

The input data for planar walls is as follows:


Friction Coefficient For frictional behavior only.

Length of l (x) edge Applies for prism cylindrical and flat surface.

Length of m (y) edge Applies for prism and flat surface.

Length n (z) Applies for prism.

Radius Applies for cylinder and sphere.

Motion Time History Defines motion in the coordinate system of the geometric entity. Applies for moving walls only.


Planar Rigid Wall Nodal Structural


Friction Coefficient(s) Only for Isotropic & Orthotropic frictional (Option 2)

Mass Only for moving walls.

Initial Velocity (Vo) Only for moving walls (Option 1). Defined relative to the local coordinate system used to define the wall.


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Note that the user must select a local coordinate system that is used when generating the geometry of the wall. The local z axis is always the n axis in the LS-DYNA definition. The velocity is defined as a time field in the local z direction.

Tied Shells

This defines a *CONSTRAINED_TIED_NODES_FAILURE data entry. Edges of shell elements be selected.

Tied Shell Edges

This defines a *CONSTRAINED_TIE-BREAK data entry. This requires a dual application region. Both master (primary) and slave (secondary) must be the edges of shells.

Nodal Rigid Body

Length of l (x) Edge Length of the l edge of a finite plane.

Length of m (y) Edge Length of the m edge of a finite plane.


Tied Shell Nodes Element Uniform Structural 2D


Plastic Strain at Failure The tied nodes, which must be coincident at the corners of each shell, separate when the average weighted plastic strain reaches this value.


Tied Shell Nodes Element Uniform Structural Dual Application


Plastic Strain at Failure The tied nodes separate when the average weighted plastic strain reaches this value.


Nodal Rigid Body Nodal Structural



This defines a *CONSTRAINED_NODAL_RIGID_BODY entry. Note that the user must define a local coordinate system with origin at (0,0,0) on the wall and x direction normal to the wall and pointing into the body. The option INERTIA will be generated if the second or third of the following options are selected:

1. Computed (no input data required)

2. Defined Globally

3. Defined Locally (Local analysis coordinate frame selected).

The input data is tabulated below.

Nodal Inertial Load

Creates *LOAD_BODY_OPTION or *LOAD_BODY_GENERALIZED entries depending upon whether the condition is applied to the complete body or some subset of the body. Note that only one scale factor can be applied to the loads. Note also that the selected coordinate system defines the centre of rotation for angular velocity.


Mass Translational mass of rigid body.

Inertia Ixx xx component of inertia tensor.

Inertia Ixy Not required if a local coordinate system is defined.

Inertia Ixz Not required if a local coordinate system is defined.

Inertia Iyy yy component of inertia tensor.

Inertia Iyz Not required if a local coordinate system is defined.

Inertia Izz zz component of inertia tensor.

Trans. Veloc (v1,v2,v3) Translational velocity.

Rot Veloc (w1,w2,w3) Rotational velocity.


Nodal Inertial Load Nodal Structural


Trans Accel (A1,A2,A3) Defines the base acceleration.

Rot Velocity (w1,w2,w3) Defines the angular velocity.

Patran Interface to LS-DYNA Preference GuideLoad Cases

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Load CasesLoad cases in Patran are used to group a series of load sets into one load environment for the model. Load cases are selected when preparing an analysis, not load sets. The usage for LS-DYNA is consistent, however only one loadcase can be selected for translation. For information on how to define static and/or transient load cases, see Overview of the Load Cases Application (p. 162) in the Patran Reference Manual.

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