continuum damage mechanics

The attached poster page has a self explanatory introduction of the Unified Mechanics Theory.

I have 2 questions regarding GTN model.

1) What does q1, q2, q3 signify in GTN damage model? What are their physical meanings. I know only their numerical values.
2) How to deal with the problem of GTN in Compression? It is working fine with tension but while in compression it is unable to converge.

Hello Everyone,

I am a beginner in FEA of composites under impact in commercial explicit code Pam Crash.I want to know why the behaviour of composite plies with CDM approach show mesh dependency?Or a more general question for me is that what makes the FE simulation of a material with strain softening behavior mesh dependence(If this conclusion is right)? Does it make any difference with regard to mesh dependency if one uses implicit codes??

Thanks

Setareh