Exponential Stability to a Contact Problem of Partially Viscoelastic Materials

In this paper we study models for contact problems of materials consisting of an elastic part (without memory) and a viscoelastic part, where the dissipation given by the memory is effective. We show that the solution of the corresponding viscoelastic equation decays exponentially to zero as time goes to infinity, provided the relaxation function also decays exponentially, no matter how small is the dissipative part of the material.