Dear Mohammed,

I suggest you to check the following for your modeling procedure:

1. in Elastic materials, Define the cohesive behavior. {t}=[E]{e}: this is the traction vector which is related to strains by stiffness tensor. therefore you have to enter these values according to the literature in which these parameters are mentioned.

2. Define a damage> traction damage> for example maximum equivalent stress criteria

3. define the damage evolution from Sub options and it is suitable to use energy method. this energy method needs a criteria (for example BK) and then fracture energies in different modes

If you have any questions, do not hesitate to ask

Yours best,

Pedram

thanks for you help.

but I tray this way and I can't draw the curve ccconstraint-strain for the contact zone. It seams like bouth items are completly free