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What's the problem causes high epsillon value?

What's the problem causes high epsillon value?

What's the problem causes high epsillon value?

(OP)
I modeled a structure using FEMAP and run the NASTRAN and it gives me a high value of epsilon (E+14). There's no singularities, nor free edge. What else could cause this problem?

RE: What's the problem causes high epsillon value?

Could be a lack of constraint.  Try running a modal analysis and see if anything is flying away.

RE: What's the problem causes high epsillon value?

If you run a modal analysis make sure you have the correct density in mass units.  Then see if there are any near zero modes.  I would expect the frequencies to be above 5Hz for most typical structures.  Regardless, the mode shapes will tell all.  You may want to exagerate the deformation past the 10% FEMAP has.  Look for any parts moving as a rigid body.  When epsilon is that high it means there are large, unrealistic displacements as well.  

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