Coupling Smoothed Particle Hydrodynamics with Finite Element Method to Simulate Residual Stresses from Friction Stir Processing

Friction stir processing (FSP) is a solid-state material processing technique that locally modifies the microstructure but also induces undesirable residual stresses. A robust numerical model for the FSP can help in mitigating these residual stresses. Heat source models within a finite element method (FEM) framework suffer from inaccuracies. In contrast, smoothed particle hydrodynamics (SPH) model that explicitly captures the material flow near the tool and the associated heat generation is accurate. However, the computational expense of SPH simulations can be prohibitive. In this work, we propose a coupled SPH-FEM framework. SPH is used to accurately model the heat generation near the tool, which is then inserted into the FEM model as a heat source. To verify this proposed coupling approach, a test case is set up with typical FSP conditions, and it is modeled in both SPH and SPH-FEM. The temperature profiles were compared after the simulations had reached steady-state temperatures. The similarity of the temperature profiles from SPH-FEM and SPH validated the proposed coupling approach. This proposed approach achieves the accuracy of the SPH method while potentially retaining the low computational expense of FEM.