Superconvergence of finite element method for the Signorini problem

In this paper, we study the superconvergence of the frictionless Signorini problem. When approximated by bilinear finite elements, by virtue of the information on the contact zone, we can derive a superconvergence rate of O ( h 3 2 ) under a proper regularity assumption. Finally, a numerical test is given to verify our result.