Interpretation of the problems found in applying contact conditions in node-to-point schemes with boundary element non-conforming discretizations

Several procedures for considering contact problems between deformable bodies using boundary elements with non-conforming discretizations are discussed in this paper. All the procedures considered (both those formerly proposed and a new one presented here) are based on an approach of strong imposition of the contact conditions, relating values of displacements and tractions of points and nodes of both bodies to force equilibrium and compatibility equations. All the procedures lead to similar results when the same general rule is followed in all cases: the body whose nodes control the displacements of the contact zone is discretized with more refined meshes. There are, nevertheless, cases, not previously referenced in the literature, where these procedures produce wrong definition of the subzones of adhesion and sliding, as well as some jumps in the stresses. These problems, whose appearance is shown to be due to the intrinsic nature of the node-to-points contact schemes, are discussed and recommendations are given to avoid them. Three classical examples belonging to the conforming, receding and advancing contact problems are studied, considering the presence and absence of friction. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.