Tensile shear and fatigue properties of titanium alloy sheet joints

In this paper, the mechanical clinching, self-piercing riveting(SPR) and resistance spot welding were applied to connect the aluminum alloy sheets. The fatigue experiments were conducted to the joints. Then the statics performance and fatigue properties were compared between the three types of joints. The results showed that the static strength of the resistance spot welding joint is the best and far higher than the others. The fatigue property of the clinched joint and the SPR joint are favorable. When the amplified applied load is high, the fatigue property of SPR joint is better. When the amplified applied load is low, the fatigue property of clinched joint is better. In the case of two million times of fatigue limit, the fatigue property of the cliched joint is the best, the fatigue property of the SPR joint is second and that of the resistance spot welding is the last. That was because the poor performance, the residual stress superposition, and the fatigue crack expansion with continuity of the thermal influence zone of the spot welding joint. However, the slight slips for mechanical joining and self-piercing riveting have effect on relaxing the concertation of stress. In this way, the fatigue property of the cliched joint and the SPR joint can be improved.