Hello,

I conducted an uniaxial tension test of a very flexible material, and obtained Force-Displacement data. From these data, by using the dimensions of the specimen, I calculated engineering stress-strain values.

When I create Material Field, should I input engineering values or real values? Calculation of real values will be extremely difficult. Does anyone knows which input should be provided?

My second question is when I implement Nonlinear Elasticity model, fatal error occurs is .f06 file. I have found in a forum that both linear and nonlinear constitutive models should be implemented and solution should then be performed. I have checked this, indeed solution is achieved. However, I wonder that whether this model initially uses linear elastic model and after a certain strain value converts to non linear model, or, it directly uses nonlinear model which means inputs of linear model are insignificant?

Thank you.