Supported Keywords Exported in Solver Deck

The mechanism information is embedded in the input deck using keywords following the /END (for Radioss), *END (for LS-DYNA), ENDDADTA (for OptiStruct/Nastran) and *END STEP (for Abaqus).

For OptiStruct, a mechanism is defined between the $MECHANISM_START and $MECHANISM_END keywords, and is composed of:
  • $ASSEMBLY defines a body with the following attributes:
    • Assembly ID
    • Assembly name
    • Number of part sets and related set IDs
    • Number of parts and related part IDs
    • Number of node sets and related set IDs
    • Locked degrees of freedom
    • Optional local coordinate system
  • $CONNECTION defines a joint between assemblies with the following attributes:
    • Connection name
    • Assembly ID #1
    • Assembly ID #2
    • Connection position (defined by Node IDs or connection position coordinates)
    • Joint limits in + and - directions
    • Current joint distance/angle value
    • Lock level
    • Assembly ID #3 (for the Double Slider only)
    • Scale factors for relative displacement between Assembly #3 and Assembly #1 and #2
  • $POSITION defines, for a stored position, the position information for the mechanism’s assemblies with the following attributes:
    • Position name
    • Assemblies position matrixes
      Note: The Reference and Initial positions should never be deleted inside the mechanism.
  • The following connection keywords can be defined depending on the type of joint created:
    • $CONNECTION_PIN defines a ball joint
    • $CONNECTION_HINGE defines a revolute joint
    • $CONNECTION_CAM defines a cam joint
    • $CONNECTION_LINE defines a cylindrical joint, or a double slider joint if assembly ID #3 is defined or a slider joint has the #HM_SLIDER_JOINT comment defined before the name of the connection