Armin Yousefi - School of Mechanical Engineering, College of Engineering, University of Tehran
Soran Hassanifard - Faculty of Mechanical Engineering, University of Tabriz, Tabriz, Iran

In the present study, the fatigue behavior and tensile strength of the aluminum alloy, joined by friction stir spot welding (FSSW), are investigated numerically. The 3D finite element model is performed to analyze the FSSW joint by using Abaqus software. The tensile test is simulated for joints, and the tensile strength is determined for both FSSW joints with probe hole and refilling one. In order to calculate the fatigue life of FSSW joints, first, the hysteresis loop is determined, then the plastic strain amplitude is calculated. Finally, by using the Coffin-Manson equation, fatigue life is predicted. The tensile strength of the joint without a probe hole (refiled hole) is higher than the joint with a probe hole. Therefore, refilling the probe hole is an effective process for structures jointed by FSSW, subjected to a static load. The fatigue strength of the joint with a re-filled probe hole is nearly the same as the structures with a probe hole at low applied loads. Also, the fatigue strength of joints with a refiled probe hole is lower than the joint with probe hole at high applied load.

FSSW, finite element model, tensile strength, fatigue life