Extended finite element method in plasticity forming of powder compaction with contact friction

In this paper, a new computational technique is presented based on the eXtended Finite Element Method (X-FEM) in pressure-sensitive plasticity of powder compaction considering frictional contact. In X-FEM, the need for mesh adaption to discontinuity interface is neglected and the process is accomplished by partitioning the domain with some triangular sub-elements whose Gauss points are used for integration of the domain of the elements. The technique is applied by employing additional functions, which are added to approximate the displacement field of the elements located on the interface. The double-surface cap plasticity model is employed within the X-FEM framework in numerical simulation of powder material. The plasticity model includes a failure surface and an elliptical cap, which closes the open space between the failure surface and hydrostatic axis. The moving cap expands in the stress space according to a specified hardening rule. The frictional behavior of contact between two bodies is modeled by using the X-FEM technique and applying the Heaviside enrichment function. The application of X-FEM technique in simulation of pressure-sensitive material is presented in an incremental manner and the role of sub-elements in simulation of contact treatment is demonstrated. Finally, several numerical examples are analyzed with special reference to plasticity forming of powder compaction.