Novel Finite Element-Cell based Methodology for Evaluating Residual Stress Distribution Caused by Punching Process in Plane Crack Problems

One of the most important factors in reducing the crack growth rate and ultimately increasing fatigue life is the creation of Compressive Residual Stress (CRS). In this regard, many well-known methods in the industry rely on Severe Plastic Deformation (SPD) as their main mechanism. Among these methods, crack tip punching has attracted significant interest across various industries. This article aims to present a novel evaluation methodology for the residual stress field with high accuracy. The proposed method, based on Finite Element-Cell (FE-Cell) approach, is specifically designed for Plane Crack problems. To validate this approach, a case study was conducted on a standard Compact Tension (CT) specimen made of A.356 aluminum alloy. The punching process was simulated considering elastic-plastic material properties and isotropic hardening. To verify the accuracy of the FE simulation, the CRS distribution resulting from the punching process was obtained using the FE-path method and compared with previously published results. The proposed FE-Cell method was then employed, and the residual stress fields around the PLC were averaged for each nodal element layer within a representative volume to determine the true residual stress distribution as a function of target depth. Eventually, the obtained results were compared with the results of FE-path method. This comparison showed that the proposed model, i.e., FE-Cell, can well evaluate the residual stress field on the surface and depth at the crack tip as a result of the punching process.