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Exclude rigid links from analysis

Creator
Creator

I have a model subject to numerous different load cases with different constraints for each case.  In some cases it is useful to use rigid links to distribute the peak loads from constrained nodes, but I would like the links to be ignored in other cases.  is this possible within a single model?

many thanks, David

2 REPLIES 2

Re: Exclude rigid links from analysis

Siemens Phenom Siemens Phenom
Siemens Phenom

When setting up a NASTRAN analysis, you have the options of specifying a FEMAP group.  With this, you can set up on e analysis set with the full model.  Then, create a group of everything in the model, less the elements you want to exclude.  Specify this group in the Bulk Data options of Model - Analysis, and you can limit what elements get written...

 

BulkDataGroup.jpg

 

Mark.

Re: Exclude rigid links from analysis

Phenom
Phenom

Hi,

I usually use 1 of 2 methods:

 

1) easy: use RBE3 interpolation elements. If constrained nodes vary, then an RBE3 with a floating (non-constrained) node is usually mute, it won't change anything in th erest of your analysis.

 

2) bit more tricky: convert your RBEs to MPCs (which is their true form). MPCs are called in the same manner than SPCs, so you can turn them on and off for each subcases unlike RBEs.

 

Useful info here:

https://community.plm.automation.siemens.com/t5/CAE-Simulation-Femap-Forum/RBE-MPC-Formulation/td-p/...

 

AP