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.
I calculated an example of unaxial tension using GTN model offered by Abaqus. I followed all the instructions found in CAE User's and Analysis User's manual in Abaqus documentation. No error or warning was issued but the result seemed ridiculous, since VVF, VVFG and VVFN keeped 0 throughout the process while equivalent plastic strain keeped increasing(which showed the material had come into plastic deformation). I don't know what went wrong, looking forward to you reply.