Andreas Koutras
Ansys Employee

Hello Oleg,

Here are the suggestions of the developer for your problem:

"SPG can use effective plastic strain, first principle stress, maximum shear strain or GISSMO damage value as bond failure criterion.  According the description from the user, my suggestions are:
  1.  MAT_ADD_EROSION with UMAT's history variable is not suggested. SPG doesn't use element erosion, but bond failure. 
  2. User can use MAT_ADD_DAMAGE_GISSMO uses HISVN to define the history variable to accumulate damage value. Then use IDAM=0 to use damage value to failure bond. Set dtype=0, don't delete elements. As I mentioned, this way is not verified with SPG. 
  3. IDAM=1 with very small EPS should work. It becomes a ductile failure.
  4. Alternative way, user can try to set the stress of material points to zero when criterion match. Then use IDAM=3 and bigger stretch to fail bond. I cannot grantee the performance since it is brittle failure. The brittle failure is very sensitive."