XFEM Analysis of Strain Rate Dependent Mechanical Properties of Additively Manufactured 17-4 Precipitation Hardening Stainless Steel

Abstract

Additively manufactured (AM) specimens of 17-4PH stainless steel corresponding to the three-point bend test, compact tension test and single edge cracks were analysed using Extended Finite Element Method (XFEM) approach. A two-dimensional and three-dimensional elastic-plastic simulation were conducted using “Abaqus 6.14” software based on the experimental results and validated with the simulation results. In XFEM, the partition of unity (PU) was used to model a crack in the standard finite element mesh. Based on simulation results, the present study compares the mechanical properties of AM 17-4 PH stainless steel samples with those of wrought 17-4 PH samples. Stress intensity factor and J integral were used to measure fracture toughness of the specimens. The change in fracture toughness with strain rate was evaluated by simulating two-dimensional compact tension specimens. The presence of defects such as pores resulting from entrapped gas, un-melted regions, and powder particles resulting from lack of fusion were the main reasons for lower elongation to failure of LPBF produced 17-4PH SS reported in the literature.