Fatigue failure analysis and lifetime prediction of self-piercing riveted dissimilar aluminum alloy joint based on energy method

The dissimilar aluminum alloy plates would be pierced by rivet, and the irreversible deformation results in fatigue life reduction of self-piercing riveted joint, compared with the base material. In order to exactly estimate the remaining life of self-piercing riveted dissimilar aluminum alloy joint, a dissipated-energy-based life span assessment method in consideration of stress concentration coefficient is presented in this paper. The mechanical properties of riveted joint and base material are obtained through monotonic tensile tests. Fatigue tests of self-piercing riveted joint are performed to capture surface temperature increment by the infrared thermal imaging technique, and fatigue failure analysis is conducted on the fracture surface. The stress concentration coefficient is determined by the numerical analysis of SPR joint under tensile loading, and then a novel dissipated-energy-based lifetime estimation approach is suggested. The predicted lifetime of self-piercing riveted joint agrees well with the tested data. The optimization design of selfpiercing riveted joint with two rivets is implemented by considering the uncertainties of the rivet position to extend lifespan, and the calculated results show that the fatigue life of the optimized riveted joint improves by 68.2%.