Review of FEM for Material Fluid in Friction Stir Welding Process

The present situation of the numerical simulation studies of the material flow in friction stir welding are introduced and summarized.It is generally accepted that there exists an obvious flow region or separating surfaces of motion if the metal around the tool is described as fluid or rigid-plastic material,which is different from practical situation.Through researching the driving force of material flow and the restriction on the flow material,namely soft restriction,the common problems that exist in the research of FSW process may be solved.This may lead to the perfection of FSW weld formation theory.