Fatigue of self-piercing riveted joints in aluminum alloy 6111

Self-piercing riveting (SPR) is becoming an important joining technique for the automotive applications of aluminum sheets. In this paper, the fatigue behavior of self-piercing riveted joints in 6111-T4 aluminum sheets is studied. Both constant amplitude fatigue tests as well as two-level cumulative fatigue tests are performed. It is observed that the rivet setting pressure, which is one of the key process parameters, influences the static failure load, but not the fatigue life. In cumulative fatigue tests, the sequence of loading is found to influence the fatigue life. Fatigue cycling up to 70 percent of fatigue life reduces the post-fatigue residual failure strength in a gradual manner; however, above 90 percent of fatigue life there is a sudden decrease in the post-fatigue failure strength. (C) 2002 Elsevier Science Ltd. All rights reserved.