Hi all,
I'm trying to implement a VUMAT on a 2D model in order to simulate the nonlinear hysteretic behaviour of the material. What I have to do is taking the stress s11 of the element and using it as input in the main algorithm, from which I have as output a delta E (the variation of the young modulus) that I have to multiply with the strain component eps1 in order to have a new stress to apply to the element of the user material.
Since that I'm new with UMAT, VUMAT etc...what I'd like to know is which variables I need to use for stress s11 and strain eps1.
For example, I tried to use stressold as input and stressnew=(E+deltaE)*straininc as the new stress to apply to the element, but I don't know if it's the right way to operate.
Regards