FEMAP strange RBE3 behavior 1

[EnginerdNate]

I had a situation in which I needed to activate some rotational degrees of freedom on the independent side of am RBE3 due to geometry (linear set of points). I noticed in the model sometime later that those same rotational degrees of freedom were activated in a different RBE3 in the model. I did some testing, and if I go Edit->Element and select any RBE3 in the model, change a DoF setting and then do Edit->Element on a different RBE3 in the model it will show that same edited set of DoFs. What gives? There isn't some limitation I'm unaware of in Nastran that requires all RBEs of a type to have the same DoFs is there?

Cheers,
Nathan

 

[EnginerdNate]

So instead of deleting this and hanging my head in shame I'll make an update for others who come across the same "issue".

I misunderstood the FEMAP interface and thought that the DOF setting in the Modify->Edit->Elements dialog applied retroactively to every independent node in the element. I was unaware that RBE3s could be specified with different DoFs on different independent nodes. Toggling the DoFs in this dialog only applies to newly added nodes unless you highlight the existing nodes and click "update".

Conversely, the "Update Elements -> Rigid DOF..." Dialog changes the DOFs on all of the nodes in the selected rigid element.

Hopefully this clears up confusion for others like myself who are learning as we go!

 

[rb1957]

excellent … no one should "hang their head" when they learn something. In hindsight many things are obvious. Thx for sharing the knowledge !

another day in paradise, or is paradise one day closer ?

 

[TG_eng]

You can also do it the original way you were trying. Just note that before clicking "Update" in the dialog, you must highlight the nodes you would like to update DOFs of. Click and hold shift and click down to the next node you would like to update to. Then you can specify which DOFs to change.