FEMAP / Nastran non-linear material function panic

[trainguy]

Does anyone out there know why after performing a non-linear analysis using function dependant (the vs.stress type)material properties, my stresses aren't related to my strains as per the function that I entered?

Can anyone tell me when to use the "vs. stress" type as opposed to the "stress vs. strain" type of function?

Thank you in advance,
GA

 

[EdR]

trainguy:

A couple of possibilities are:

1. You have an error in entering the properties
2. You have entered properties for a uniaxial stress state (e.g Youngs Modulus) but you are viewing the results from a bi- or triaxial stress state where all 3 of Hookes Law equations are required to relate stress and strain...not simply sigma = E epsilon

I am not familiar with your nomenclature of "vs stress" type so can't offer an opinion.

Hope this helps

Ed.R.