Hello,

I have material data were voids form under tension but not under compression. I can consider this effect using the triaxiality parameter in the ductile damage model. 

However, I am wondering if I should use the (true) stress strain curve from the tensile or the compression case under "plastic"?

I attached a small example of the graph. "2" is the tensile case and the one above the compression load case (the difference at the end is roughly 30 MPa, so it is significant).