A mortar segment-to-segment contact method for large deformation solid mechanics Original Research Article

Contact modeling is still one of the most difficult aspects of non-linear implicit structural analysis. Most 3D contact algorithms employed today use node-on-segment approaches for contacting dissimilar meshes. Two pass node-on-segment contact approaches have the well known deficiency of locking due to over-constraint. In this work, we develop and demonstrate a segment-to-segment contact approach based on the mortar method. By eliminating the over-constraint, this method appears to be much more robust than the node-on-segment approach. Furthermore, node-on-segment approaches suffer when individual nodes slide out of contact at contact surface boundaries or when contacting nodes slide from facet to facet. This causes jumps in the contact forces due to the discrete nature of the constraint enforcement and difficulties in convergence for implicit solution techniques. These jumps in forces are avoided in the segment-to-segment approach, since penetration is measured by the occluded weighted volume which varies smoothly with perturbations.