Global-local w/ solid model - coupling boundary nodes to new mesh?
Global-local w/ solid model - coupling boundary nodes to new mesh?
(OP)
I'm trying to do a global-local analysis of a solid model in Nastran for Windows 2003. The global model has been solved, and the original nodes on the sub-structure boundary surfaces have 6dof constraints and displacement loads derived from the output vectors. The tricky part is trying to tie the original boundary nodes to the new local mesh. I've tried keeping the original discretization on the boundary surfaces, but the mesher consistently fails to include all of the hard points, or generates distorted elements that fail Nastran's checks during the solution. Remesh>Refine only works with 2D elements. The automatic commands for mesh transitions, closest link, etc. don't connect the correct nodes.
Is there a straightforward method for doing 3D global-local in N4W?
Is there a straightforward method for doing 3D global-local in N4W?





RE: Global-local w/ solid model - coupling boundary nodes to new mesh?
RE: Global-local w/ solid model - coupling boundary nodes to new mesh?
Otherwise for MSC you are out of luck. Some suggestions:
1. Keep the nodes on the boundary meshed the same. Then convert these output displacements in FEMAP to enforced displacements as loads for the local model.
2. Use MPC equations to enforce the displacement field of the global model.
3. Use MPC equations to interpolate the global displacments to local nodes.
RE: Global-local w/ solid model - coupling boundary nodes to new mesh?
Why not make sure the nodes have identical id's in both models, then read the data from local to excel, and then from excel to global.
If you have the full Nastran (from your post I unfortunately doubt that) you kan use superelements. Otherwise you can study the comcept of superelement, it might give some ideas.
Good Luck
Thomas
RE: Global-local w/ solid model - coupling boundary nodes to new mesh?
Although I understand how to apply MPC equations, I have no idea how to formulate such equations for an arbitrary surface with an irregular distribution of dependent and independent nodes.
What does transferring the data to and from excel accomplish?
RE: Global-local w/ solid model - coupling boundary nodes to new mesh?
Or you can write your own Refine commands in the API.
Regards
Thomas