Hello,

I am trying to simulate crack formation in the soft tissue (for example skin) by indenting a non-sharp instrument in it using XFEM method.

The simplified case of simulation is a puncture of tissue by a relatively smooth plate to split it in half (see Pic.).

The most important moment is that the crack location is not known, so the cohesive elements can’t be used.

Unfortunately, XFEM works relatively well with hard materials but does not form a crack in soft tissue. The damage criterion is based on traction-separation law, because it seems the only suitable way to describe the damage in tissue.

Model: Tissue - elastic deformable shell, instrument - analytical rigid, contact - surface to surface, tissue constrained at the bottom. Input file is attached.

Maybe it is not the suitable method at all. Any advice or suggestions would be highly appreciated.