An Alternative Pressure-dependent Friction Boundary Condition for Modeling Self-reacting Friction Stir Welding

Abstract A pressure-dependent friction boundary condition is developed based on wear theory for modeling self-reacting friction stir welding using computational fluid dynamics approach. The importance of shear layer in weld formation is emphasized. Effects of welding speed on the weld cross section geometry can be robustly captured with this newly developed boundary condition. Computational results showed at higher welding speed, the distance between the TMAZ boundary and the pin periphery at the advancing side is reduced, which corresponds to the experimental observations. This tendency could serve as a numerical criterion to predict void defect formation.