Mortar Contact Algorithm for Implicit Stamping Analyses in LS-DYNA

A challenging task for the static implicit nonlinear solver in LS-DYNA is to accurately and robustly solve contact problems, especially is this needed for stamping simulations. This paper aims at investigating the benefits of a mortar segment-to-segment contact algorithm by Puso and Laursen [1,2] when compared to the traditional node-to- segment approach. A penalty based version of the algorithm is implemented in LS-DYNA, meaning that the contact tractions are proportional to both the penetration as well as the overlapped area of segments in contact. This allows for the nice property that the resulting global contact force is continuous with respect to deformation and thus makes the approach intuitively suitable for implicit analyses. Further measures for smoothing the response are implemented in the method and the first tests indicate that the method is advantageous at least for a certain class of problems, but how great the overall impact will be remains to be seen.