Model runs for analysis but not for optimization
Hello,
I try to run an optimization run (see file attached).
When running analysis it's okay, but when running optimization I have the message
The rotational displacement has large magnitude, -178164 degrees
At beginning of .out of optimization I have this information:
*** INFORMATION # 815
The total number of rigid elements, whose rotational dependent d.o.f.
are removed because there is no need to constrain those d.o.f., is 3.
I don't understand if my optimization error is coming from this automatic removal or from something else?
Thank you very much!
Stéphane.
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Ok beginner mistake!
So I guess Optistruct creates autospc for linear static solving, but don't do it for optimization solving.
Thnak you very much!
Hi Stephane,
I believe the message happened because the RBE2 is only constrained in DOF 123 in both locations. So, the model is freely rotating about the axis between the two constraints when the load is applied as there is no DOF fixed in rotation.
The rotational dependent DOF message is occurring because the RBE2s are connected to solid elements which don't have rotational DOFs to constrain. Making the switch to constrain DOFs 456 is one way to allow the optimization to run- I'll attach the fem model.
Thanks,
Rob H.