An in-situ defect detection method for aluminum alloy bobbin tool friction stir welding assisted by lateral force

Abstract

This paper proposes a force-driven method for in-situ defect detection in aluminum alloy bobbin tool friction stir welding (BTFSW). The variations of the three component forces in BTFSW, including traverse force (Fx), lateral force (Fy) and plunge force (Fz) are studied. The mean value of Fy exhibits the highest correlation with tunnel defects. Numerical simulation results show that higher stress on the retreating side due to insufficient material flow and severe material jam results in an abnormal increase of Fy for defective joints, revealing the response mechanism of Fy to tunnel defects. The proposed method offers a promising approach for real-time detecting tunnel defects in aluminum alloy BTFSW.