MSC/NASTRAN
Writing an MSC/NASTRAN output file creates an MSC/NASTRAN file in ASCII format called filename.nas.
The following table lists the mesh elements written to the MSC/NASTRAN output file for the various mesh types, idealizations, and simulation entities.
Element Type
MSC/NASTRAN
Shells
Triangular—Linear
CTRIA3
Triangular—Parabolic
CTRIA6
Quadrilateral—Linear
CQUAD4
Quadrilateral—Parabolic
CQUAD8
Tetrahedral Solids
Linear and Parabolic
CTETRA
Beams
CBEAM
Trusses
CROD
Springs
CBUSH
Masses
CONM2
Rigid Links
RBE2
Weighted Links
RBE3
Gaps
All
CGAP (element coordinate system and orientation)
PGAP (properties)
Contacts
Linear Structure
BCONTACT
BCTABLE (Defines contact table)
Parabolic Structure
For contacts, stiffness properties are specified on the PGAP card. These properties include UO, the initial contact value, KA, the normal stiffness, and KT, the slide stiffness. MSC/NASTRAN supports zero-length idealizations—idealizations that have no length, such as an idealization between a point on a surface and the surface itself—for contacts and advanced springs only.
For shell elements, Creo Simulate writes value of the offset between node location and the midsurface if the shell pair is placed on the red or yellow surface or on any selected surface. If the offset is not uniform or taper across the element, Creo Simulate calculates an average value of the offset. NASTRAN uses the offset value as an input for ZOFFS in the element card images.
If the sim_check_jacobian_corners configuration option is set to yesCreo Simulate adds the executive section card GEOMCHECK TET_DETG MSGTYPE=FATAL to the NASTRAN output file filename.nas.
For an MSC/NASTRAN solution, you can use the fem_solver_time_limit configuration option to interrupt the solver after a specified time limit in minutes. The default value is –1. This negative value allows MSC/NASTRAN to set its own default time limit.
If you place simulation entities on layers and want to review a file containing layer data, you can use the sim_output_ids_for_layers configuration option to generate an XML file that lists the layers. Creo Simulate outputs this file at the same time that it outputs the .nas file and places it in the same directory as the .nas file.