Checking cyclic symmetry BC with FEMAP and NE NASTRAN

[jerzy]

I have been trying to find a listing of the constraint equations created when
the CYSYMGEN command is added to my input files created in FEMAP. Most of the problems I've
run with cyclic symmetry give reasonable results but sometimes results are far from what I would expect and I would like to see what MPC were created to implement the cyclic symmetry.
I turn on the TRSLMODLDATA command, but can't find anything indicating the symmetric boundary conditions in the BDF file. I update the nodal definition and output coordinate systems and
define the elements in the default cylindrical coordinate system in which the model is created.

I would appreciate any suggetions.

Thanks

Jerzy

 

[jerzy]

Hello forum members,

I hadn't looked carefully enough at the text listing of the BDF file: I found the MPC listings in there.
I had expected to import the BDF file back into FEMAP and see the listings there. I get an error when I import the
BDF file, but I can read the MPC equations from the BDF text file.

Has anyone else been using the CYSYM commands in NE NASTRAN, and what kind of results have you been getting?

Thanks

Jerzy

 

[kalinka]

When MPC equations are generated internally in NEi Nastran there’s a default set id of 0. The 0 set is always run with every subcase, but that set id causes issues for Femap. Until Femap fixed their program, you get around it by changing the set id to something else (like 1) to ensure the results are properly imported.

CYSYMGEN Case Control command generated the MPC equations needed for cyclic symmetry. Also, set MODLDATAFORMAT=1 and in the .OUT will be the MPC equations explained in tabular form.

Cheers,