I have a perturbation analysis with contact using the LCP solution technique, and I want to include this model in a topology optimization workflow. Let’s say I have some nodes on the surface of a part which may be in contact, and I would like to constrain the maximum internal forces they experience. My questions are:

1. If the contact status is open at the beginning of the step but it gets closed at the end, are contact forces taken into account in the sensitivities of the internal forces at the nodes(+elements) involved in contact?
2. Do the computations differ when contact is closed at the beginning of the step?
3. Do you have any source I could consult to understand a bit better how adjoint sensitivities are computed when the step involves contact? I could not find such information in the Abaqus theory or user guides.

 Thank you in advance for your help!