Wear Model - Solving a contact problem with irregular geometry

Dear COMSOL,

I wonder if you could help me in solving this contact model in COMSOL 4.3. I am implementing wear by solving a quasistatic contact model using the Structural Mechanics module, extracting the results (contact pressure etc.) into COMSOL with MatLab and calculating wear, and interpolating two new ‘worn’ surfaces into the model geometry for which I need to solve a contact problem once more.

The problem with the wear process is that the surfaces become rather irregular (see attachment) after a few iterations. I cannot get the model to solve for the next iteration (actually it solves for the first half of the parametric sweep but not the second) .

Do you have any tips on how to get such a model to solve? A difficulty I am finding is in choosing the correct initial value for the contact pressure. Also, I don’t understand the ‘Normal Contact’ options within the ‘Contact1’ node of solid mechanics – can anything here be used to help the solution converge?

Thanks in advance for any help you can offer me.

Kind Regards,
Dan