Hi, I am trying to simulate the structural behaviour (2 cases: static and dynamic) of an EPP(expanded polypropylene)-foam platform being part of an assembly. I have stress-strain data from both the uniaxial tension and compression tests. I tried to approximate it with hyperelastic models (not sure though if this is the best choice) but I could not get an acceptable curve-fit with any of them (separately, several models like Polynomial or Ogden make a pretty good job "curve-fitting" the test data but when I try to fit the whole range of available data combining both tests data nothing works...).
A second doubt is about the right Failure Criterion for this kind of materials: I opted for Mohr-Coulomb as a conservative choice for brittle materials but again, not sure if it is the best option.
Anybody experienced with this kind of polymer foams or with any idea/suggestion? Thanks, it´ll be appreciate it.