FEMAP REB3 behaving like RBE2

[autothesis]

HI..
I have modeled RBE3 with 6 DOF's for (one)Dependent Node and 3 DOF's for (many) Independent Nodes.
But, when I display the deflection, the RBE3 doesn't move at all with rest of the structure. It rather holds back all the attached nodes firmly. It seems like acting as RBE2.
And I have checked and made sure that it is modeled as RBE3. Has any body come across something like this before.

 

[jbrackin]

Can you provide a few details?
Are you basing this observation(RBE grounding the motion) strictly on the a deformed shape plot in Femap? What version of Femap? Did you actually look at displacement values from the connected nodes?
Is this a static solution?
Have you inspected the f06 file for warnings and errors in the solution?
In bulk data options, did you check "AUTOMPC"?
What kind of loading is applied? mechanical only? temperature loading?

 

[autothesis]

It is just a static loading. I checked off the AUTOSPC. It is just the deformation contour what i am checking. I didn't check node deformation. I am using version 11.0. No errors in f06.
.dat file shows the element modeled as RBE3. but its acting too rigid. Center node doesn't move and won't allow the dependent nodes to move also.

 

[jbrackin]

AUTOSPC and AUTOMPC are two very different things, pay careful attention to what is checked.
Check your actual deformations either via data table of just the selector to interrogate individual node displacements.
Are they zero or do they have some value?
did you apply constraints to any of the connected nodes?

 

[BlasMolero]

Hello!,
Without the model in hand is difficult to say what is really happening, maybe you have "hidden" permanent constraints prescribed to independent nodes, RESET ALL VISIBILITY OPTIONS (just under MODEL INFO click the third icon) to see the full model details, or better upload your Femap model or the nastran input file *.dat and we will take a look to it.
Best regards,
Blas.


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Blas Molero Hidalgo
Ingeniero Industrial
Director

IBERISA
48011 BILBAO (SPAIN)
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[autothesis]

HI ..Thanks for your help.
All I did is delete and recreate the RBE3. And it is working fine now.
I think the problem was one of the node. It might be sharing a bar and also the mass element connection. But anyways. Its working for me now.