A non-penetration FEM-MPM contact algorithm for complex fluid-structure interaction problems

Abstract The improved coupled finite element material point (ICFEMP) method is an effective way to deal with fluid-structure interaction problems. However, the FEM-MPM contact algorithm employed in ICFEMP suffers from the contact penetration problem which limits its application in engineering. In this paper, the reason leading to the penetration phenomenon is revealed. The singularity of the normal vector of two adjacent surfaces makes the contact position not well-defined around at the joint line, so that particles near the joint line may penetrate the contact surface. An improved local search method is proposed in this paper to eliminate the penetration. In addition, an iterative process for imposing contact forces is proposed as well to overcome the difficulty that contact conditions can hardly be satisfied simultaneously for all contact pairs caused by the interaction among them. Numerical results illustrate that the proposed contact algorithm thoroughly eliminates the penetration phenomenon even in complex engineering problem such as the airbag simulation.