Has anyone used MAT_154 in LS-Dyna, to model an indentation test on a polymer foam material? I'm having a problem understanding the failure criteria implemented in the model. Apparently it's based on volumetric strain, but when I model a simple 1*1*1 element, it doesn't fail at the given volumetric strain value, but fails at a higher value.
I'd appreciate it if anyone with experience working on this model could advice. Thanks a lot