Fatigue life estimation of self-piercing riveted aluminum joints under mixed-mode loading

Fatigue tests were conducted using cross-shaped specimens with aluminum alloy (Al-5052) plates. Mixed-mode loading was achieved with different loading angles of 0°, 45°, and 90° to evaluate the fatigue strength of the self-piercing riveted (SPR) joints under mixed-mode loading. On the basis of a lifetime of 106 cycles, the load amplitudes corresponding to the fatigue limit were 37%, 18%, and 19% of the monotonic strength for load angles of 0°, 45°, and 90°, respectively. The equivalent stress intensity factor can appropriately predict the experimental fatigue lifetimes of SPR joints as longer than 105 cycles.