Shear strength and failure mode of self-piercing riveted similar and dissimilar materials

Self-piercing riveting (SPR) has been used to join similar and dissimilar materials for vehicle body application. In order to understand the failure mechanism and develop a method to estimate the shear strength of SPR similar and dissimilar materials, finite element modeling was conducted in this study. In the modeling, the contact conditions between the rivet and the workpieces were taken into account to establish the failure criteria of SPR of steel and aluminum sheets. It was found that the failure procedure of riveted dissimilar materials was different from that of riveted similar materials. Furthermore, the experiments were conducted to validate the modeling results. It was shown that the shear strength and failure mode of SPR joints were in agreement with the modeling results. These results suggested that the model could be used to estimate the shear strength of SPR joints. The factors influencing the failure mode and shear strength of SPR joints were discussed in detail. For rivet pull-out mode, the rivet open angle at the upper sheet, friction coefficient between the rivet and sheet, and the yield strength of the substrate were the key factors. For sheet tearing mode, failure occurred at the weaker sheet and the shear strengths mainly depended on the sheet gage and strength grade of the weaker sheet.