Review on modelling of friction stir welding using finite element approach and significance of formulations in simulation

Friction stir welding (FSW) is a solid-state joining process, which is gaining significance in many joining applications, by overcoming the limitations of other fusion welding processes. For successful incorporation of its potential during industrial applications, mechanism of joining needs to be properly comprehended. The solution lies in developing effective and reliable finite element (FE) model of the FSW process, which would help in getting an insight of the process phenomena (like material flow, heat generation, etc.) during the process. The overall result could be used to observe the effect of process parameters on weld quality. Several attempts have been made to develop an FE model for FSW using different techniques. However, building an efficient model that emulates reality is still to be realised. Here, a review is made to know the current state of various FE modelling techniques and identifying better techniques for simulating FSW and its variants. This review also highlights shortcomings (for ex: mesh distortion, simulation time, the capability of defect prediction) of previous models and discusses on grey areas which are still to be addressed in the broader perspective of FSW and its allied processes using FE approach. [Submitted 06 July 2017; Accepted 29 September 2018]