A friction stir welding model using computational fluid dynamics

Accurate simulation of the FSW process will enable rapid development of the process in particular with regard to tool design. However, this type of simulation requires a 3-D, fully coupled thermo-mechanical, solid based model with associated high computational cost. In previous work, some of the authors have demonstrated that a 2-D model using a commercial fluid dynamics code and an appropriate user defined viscosity law can accurately capture many of the trends observed in FSW. The fully thermo-mechanically coupled simulations may be run in a few hours on a PC based system. The low computational cost for this model enables rapid assessment of the effects of various material properties and the criticality of inclusion or exclusion of some property details. In this paper, the effects of varying thermal diffusivity, viscosity, etc. on the trends in x-axis forces, required torques, and potential weld defect formation are studied. The model trends are compared to experimental observations wherever possible.