Cyclic Symmetry and FEMAP
Cyclic Symmetry and FEMAP
(OP)
Has anyone found a good way to set up cyclic symmetry in FEMAP?
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Cyclic Symmetry and FEMAP
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RE: Cyclic Symmetry and FEMAP
Garland E. Borowski, PE
Borowski Engineering & Analytical Services, Inc.
www.borowskiengineering.com
RE: Cyclic Symmetry and FEMAP
For true cyclic symmetry using NEiNastran V8.4 you skip the boundary conditions and just use new CYSYMGEN param which automatically sets up MPC equations on the boundaries which force cyclic symmetric behavior.
RE: Cyclic Symmetry and FEMAP
Garland, the model has torsion applied to it so ordinary symmetry conditions would not represent the behavior of the problem correctly. Cyclic symmetry makes the nodes on the symmetry planes move together in the appropriate degrees of freedom.
RE: Cyclic Symmetry and FEMAP
Garland E. Borowski, PE
Borowski Engineering & Analytical Services, Inc.
www.borowskiengineering.com
RE: Cyclic Symmetry and FEMAP
1. In FEMAP create a cylindrical coordinate system on the axis about which symmetry exists
2. Mesh the model in this coordinate system
3. In FEMAP, MODIFY/UPDATE OTHER/OUTPUT CSYS set all nodes on the symmetry boundaries (or just all nodes) to the coordinate system defined in 1. If not CYSYMGEN will not work.
4. In FEMAP add these two lines assuming the coord. sys. in 1 is numbered 3.
PARAM, CYSYMGEN, 3
PARAM, CYSYMTOL, 1E-4 or whatever is appropriate.
Thanks for the help. :)
RE: Cyclic Symmetry and FEMAP
The definition coordinate system also has to be the same cylindrical system as the output coordinate system or CYSYMGEN doesn't seem to be able to pick the right nodes.
If you set this parameter:
TRSLMODLDATA=ON
you can check that the MPCs where created correctly.