Contact mesh approach in explicit finite element method: an application to a severe contact problem

The contact problem in Finite Element Method formulations is characterized as an optimization problem, in which the boundary conditions generate a contact penetration gap that must be minimized to maintain the physics of the problem. Normally the contact initiation depends on a search frequency and bodies’ velocities, resulting inconsiderable errors when in severe contact cases. So this work aims to propose a contact mesh approach in an Explicit Finite Element Method. This contact mesh links the probable contact regions and minimizes the potential error. To validate the material formulation and properties a tensile strength experiment was simulated. And in order to test the method efficiency, a microindentation experiment that represents a severe contact problem was simulated using explicit and implicit time integration methods. As results both methods showed similar good results when compared to experimental tests, but the implicit approach had better results in total time execution. It was possible to understand the deformation phenomenon in the microindentation test and also other related phenomena, such as the stress field and the pile up.