Static mechanical properties and failure mechanism of self-piercing riveted aluminum alloy joint

The static mechanical properties of self-piercing riveted (SPR) joints with different structures were investigated by static mechanical tests. The experimental data were analyzed by statistics in Student’s t distribution to verify the effectiveness of the data. The failed surfaces of wide joints were observed with scanning electron microscopy (SEM) to study the failure mechanism. The results show that the static mechanical properties of SPR joints could be enhanced by improving the wideness of sheet and especially the number of rivets. The macroscopic static failure mode of joints was pull-out of lower sheet. The deformation of substrate was influenced by the wideness of sheet and number of rivets. The analysis of SEM indicates that the state of upper sheet was mainly tensile, and dimple structure presented at failed location, both influenced the failure displacement of joints. The tensile and compressive states existed in the lower sheet, which affected the strength and displacement of joints.