Preliminary Study on Modeling of the Deformation and Thermal Behavior of FSW using SPH Approach

Material flow in the solid-state Friction Stir Welding (FSW) is quite a complex process. Investigation of material flow can be carried out either by experimentation or by numerical simulation. However, compared to experimentation, numerical simulation is inexpensive, efficient and convenient, but quite challenging to model. The challenging issue in modeling FSW is to deal with the large deformations of the workpiece material. The Lagrangian simulations of FSW show that the severely distorted finite elements are caused due to the large deformation of the workpiece material, which makes the Lagrangian approach inappropriate for modeling FSW. A good alternative is to study it in a SPH environment. SPH formulations are used to overcome the shortcoming of Lagrangian formulations due to its continuous regimes. The basic idea of the SPH approach is that the mesh is obliged to follow material flow. Thereby the excessively distorted elements can be avoided as in Lagrangian formulations. In this paper, we fulfill this aim by using a SPH method. We also intend to do some preliminary experiments about weld strength .An important consideration in applying the SPH approach is an advection method which determines the mesh motion in every step of the analysis. Based on the simulation results, it is concluded that the material motion characteristics on the top surface and through the depth (volume) of friction stir welds have been made for the advancing and retreating sides. The motion trends are consistent with the reported published experimental evidence.The present paper organized as following. First SPH modelling performed .After that thermal history validated with FE model. Temperature history data is in good agreement with FE model.