Free Free analysis in abaqus?

[SGKumar94]

I had to perform a free free analysis in abaqus.
But the analysis is throwing error for unconnected region or over constrain.
Is is possible to run abaqus frequency analysis without any boundary conditions.
By running the model without boundary can we get six rigid body modes in abaqus?

 

[cooken]

I routinely do this as part of model checking, so yes very much possible and a recommended step.

Please provide more detail so folks on here can help diagnose the exact cause. Are they errors or just warnings?

 

[IceBreakerSours]

Yes, you can run a modal analysis in Abaqus.

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[SGKumar94]

Yes we can run modal analysis in abaqus.
Usually we will run this analysis to check the connectivity of the assembly, But we will have boundary conditions.
My file has no boundary conditions specified.
[highlight #FCAF3E]*STEP
*FREQUENCY, EIGENSOLVER = LANCZOS, NORMALIZATION = MASS
40,0.0 ,,,,
*END STEP[/highlight]
I am getting an error only when i try run it without any boundary conditions.
***ERROR: LANCZOS EIGENSOLVER ENCOUNTERED NUMERICAL SINGULARITY OR ZERO PIVOT.
THIS MAY HAPPEN IF A BOUNDARY OF THE COMPUTATIONAL INTERVAL IS VERY
CLOSE TO AN EIGENVALUE, THE PROBLEM HAS AN UNCONNECTED UNCONSTRAINED
REGION WITH ZERO MASS MATRIX, OR A SYSTEM IS OVERCONSTRAINED.
Can we get six rigid body modes in abaqus?