Numerical Simulations of Friction Stir Spot Welding Process Using Coupled Eulerian–Lagrangian Approach

The friction stir spot welding process involves many complex problems with thermal–mechanical coupling, boundary contact, and large deformation. Among these problems, large deformation is the most difficult to deal with conventional finite element method. In this study, 3D thermal–mechanical coupling finite element analysis based on the Coupled Eulerian–Lagrangian (CEL) method is employed to simulate the friction stir spot welding process of two aluminum sheets. The computational temperature histories at different locations and the weld thermal heat-affected zones are compared with those measured from experiments. The computational results are in relatively good agreement with the experiments. The CEL approach shows no mesh distortion and can be applied for extreme deformation problems; temperature diffusion, material flows, and mixture zone results can be obtained to evaluate the quality of the joint; CEL approach is computation cost where the mesh need to be refined.