Numerical Analysis of a Frictionless Contact Problem for Elastic-Viscoplastic Materials

We consider a mathematical model which describes the unilateral quasistatic contact of two elastic-viscoplastic bodies. The contact is without friction and it is modeled by the classical Signorini boundary conditions. The model consists of an evolution equation coupled with a time-dependent variational inequality. It has been shown that the variational problem of the model has a unique solution. Here we consider numerical approximations of the problem. We use the nite element method to discretize the spatial domain. Spatially semi-discrete and fully discrete schemes are studied. For both schemes, we show the existence of a unique solution, and derive error estimates. Under appropriate regularity assumptions of the solution, we have the optimal order convergence.