Hi Mohammed,

The cohesive interaction parameters depend on the problem (and material) you are trying to solve.

You should probably look into literature (and if not, perform experiments) to find correct values (to validate) representing your model.

In general, you need to define traction separation behaviour, damage initiation criteria followed by damage evolution law.

I attach a document where you can find some tips for modelling techniques.

All the best.

think you so much