A numerical investigation on the local mechanical behavior of a 316-L part during and after an EDM basic electrical discharge

Abstract

This study proposes a novel numerical approach to elucidate the mechanical behavior of the EDMed layer during an electrical discharge and enhance the numerical prediction of the EDM-induced residual stresses and work hardening, through advances at the levels of models, loads, and boundary conditions. In this work, a single-pulse discharge was simulated using finite element method carried out in ABAQUS/Explicit code. A fully coupled thermomechanical consistent model was developed based on a hydrodynamic Gruneisen-type behavior for the hydrostatic part of the stress, coupled with a Johnson-Cook plasticity model that takes into account a strain-rate-dependent stress in the range of a shockwave condition. A time-dependent heat source and pressure pulse are concurrently applied on the workpiece-loaded boundary. Numerical results highlighted relevant findings, especially the pre-eminence of the uniform distribution of the heat flux to predict the in-depth residual stress profile and the evident effect of the plasma-induced pressure on the work hardening and less on the residual stresses.