Tensile-Shear Fatigue Behavior of Aluminum and Magnesium Lap-Joints obtained by Ultrasonic Welding and Adhesive Bonding

The present research is part of the HY-LAP (HYbrid LAP-joints) project carried out at the Dept. of Mechanical Engineering of Politecnico di Milano in collaboration with the MUSP laboratory of Piacenza and the University of Parma. In particular, the present study deals with the fatigue behavior of hybrid lap-joints (obtained by USMW plus adhesive bonding) made of light alloys thin sheets. Fatigue tests were carried out at different stress ratios (0.1, 0.3 and 0.7) finding that a different failure mechanism takes place with higher applied mean stresses. The S-N results then allowed to appreciate the better performance of the hybrid joints with respect to the application of USMW alone, while the direct comparison of the fatigue behaviors of AA6022T4 and AZ31B alloys allowed to draw some interesting conclusions