Hi Juan!

Certainly its the HCRIT parameter. It determines how far surfaces may penetrate
each other during contact interaction.
Internally the contact problem is described through a penalty formulation. This
means that if you choose HCRIT very small, the stiffness matrix becomes ill
conditioned and the solver runs into problems.
Therefore you should increase HCRIT by some order of magnitude.

Hope this helps.

Regards, Mike

___________________________
Dipl.-Ing. Michael Stadler
Computational Biomechanics
Graz University of Technology, Austria
[log in to unmask]
http://www.cis.tu-graz.ac.at/biomech/



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%