Numerical Studies on Fatigue of Tool in Friction Stir Welding

A static model and a fatigue model of rotational tool in the friction stir welding process were established respectively with ANSYS Workbench and ANSYS nCode Designlife. The effects of forward resistance, lateral force, longitudinal force and torque on the fatigue life were investigated based the load history of forces on the tool and the expression of torque. The results of numerical simulation show that the fatigue failure of tool always occurs in the root of pin, which results from stress concentration. The forward resistance is a major cause of the fatigue failure. The lateral force and the torque are the secondary causes of fatigue failure. Moreover, the longitudinal force can increase the fatigue life of the tool.