Engineering Solutions

LS-DYNA Interface Overview

LS-DYNA Interface Overview

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LS-DYNA Interface Overview

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This section describes the Engineering Solutions LS-DYNA interface. Engineering Solutions provides a complete pre-processing environment for preparing LS-DYNA data decks for analysis. Engineering Solutions can read existing LS-DYNA decks, create a model, display and edit LS-DYNA cards as they will look in the deck, and write a deck for analysis. Although Engineering Solutions also offers limited post-processing capabilities in results translation you are strongly encouraged to exclusively use HyperView. To create LS-DYNA decks in Engineering Solutions, you must load the LS-DYNA user profile with the appropriate template to access the full pre-processing capability.

The following are the general comments about the Engineering Solutions Interface for LS-DYNA

Import and Export
•The LS-DYNA interface supports the following versions of LS-DYNA: 971_R7.0, 971_R6.1, 971, 970, and 960.
•The LS-DYNA input translator supports reading both free and fixed formats, however, the export template writes all cards in fixed format. Solver specific import options are available during import in the solver options tab.
•The LS-DYNA input translator can read DUMMIES with the tree structure in Primer format or in HyperMesh format but exports the tree structure only in HyperMesh format.
•The LS-DYNA input translator allows reading multiple instances of same include file using *INCLUDE_TRANSFORM. They are read in but duplicated as independent includes inside HyperMesh. The duplicate instances of same include are tagged as not exportable thus limits the support to I/O only.
•Although majority of LS-DYNA keywords are supported, unsupported material and property if it exists in the deck are read into HyperMesh and exported maintaining the associvity. All other unsupported portion of deck is mapped to unsupported cards in HM and appended at the end of deck during export.
•Most of ID’s in the solver deck are preserved with introduction of ID pool concepts in HyperMesh. However solver cards mapped to Groups are renumbered if there is a conflict of ID among the keywords mapped to a HyperMesh entity. The new ID’s are posted during the import process.
•The LS-DYNA interface supports a smart, reliable FE input reader that warns you when your input deck contains unsupported fields and unsupported data lines for materials, properties, and control cards. It will also detect unsupported fields that have a field width that is greater than ten.

This reader cannot detect unsupported lines for keywords whose title gets written only once when there are multiple instances of the card. This occurs for the following keywords: *SECTION_BEAM, *SECTION_DISCRETE, *SECTION_SEATBELT, *SECTION_SOLID, *SECTION_TSHELL, *SECTION_SPH, *SECTION_ALE1D, *SECTION_ALE2D, *EOS Cards, *HOURGLASS, *INTEGRATION_BEAM, *INTEGRATION_SHELL, *SECTION_SHELL, *CONSTRAINED_JOINT_STIFFNESS_GENERALIZED, *CONSTRAINTED_JOINT_STIFFNESS_FLEXION, *CONSTRAINED_JOINT_STIFFNESS_TRANSLATIONAL.

 

Duplicate ID’s
•Several LS-DYNA keywords are mapped to one HyperMesh entity in some instances. By default the LS-DYNA interface doesn’t allow duplicate ID within the same HyperMesh entity with exception of elements while LS-DYNA allows duplicate ID’s across cards mapped to one HyperMesh entity. In HyperMesh ID flexibility similar to LS-DYNA can be enabled by switching on Duplicate ID option in Preferences menu.
•Duplicate ID's are supported for the following HyperMesh entities in the LS-DYNA user profile: elements, properties, entity sets, sensors, Load collectors and control volumes.

 

Mass Calculations
•Mass supplied by *PART_INTERIA card is used instead of calculating the mass based on the individual elements. Also, mass calculations include the mass supplied on the *CONSTRAINED_NODAL_RIGID_BODY_INERTIA cards.
•Shell element thickness for volume calculation is one of the following:
othe thickness on the first node for uniform thickness shells
othe average thickness at three or four nodes for non-uniform thickness shells
•The thickness values come from the *SECTION_SHELL card, unless a *ELEMENT_SHELL_THICKNESS card is defined for an element. If an *ELEMENT_SHELL_THICKNESS card is defined, its thickness values override the thickness values from the *SECTION_SHELL.
•Integrated beams have an area equal to the average of the two end areas. Resultant beams use the area entered on the *SECTION_BEAM card. The volume is calculated by multiplying the length of the beam with the *SECTION_BEAM card area. Discrete beams use the volume supplied by the *SECTION_BEAM card. In all cases, if an *ELEMENT_BEAM_THICKNESS card is defined for an element, then the element values override the *SECTION_BEAM values.
•Only element masses are considered. Other mass specifications, such as on a rigid wall card, are ignored.

 

See Also:

Model browser

Solver browser

Connector browser

Include Files

Using the LS-DYNA Utility menu

Supported LS-DYNA Keywords

Unsupported LS-DYNA Keywords

Solver Conversion