Contribution to free boundary problems using boundary elements: Trefftz approach

There are two main approaches to the formulation of boundary methods, these are boundary integral equations and approximations by complete systems of solutions (Trefftz method). The latter has been the subject of extensive studies by one of the authors oriented to clarifying the foundations of the method and increasing its versatility. The present paper is devoted to explain the application of this procedure to free boundary problems such as Signorini and friction problems in elasticity.