Effect of repeated impacts on the mechanical properties of nickel foam composite plate/AA5052 self-piercing riveted joints

Abstract

Due to their good impact resistance, foam metal composite plates are widely used in the lightweight multi-structure design of cars, and nickel foam is one of the commonly used foam metals. In this paper, the nickel foam composite plates were manufactured, and the self-piercing riveting was used to join the nickel foam composite plates with AA5052 aluminum alloy. The impacts of different energies and times ont the joints were investigated, and the mechanical properties and failure forms of the impacted joints were analyzed. The results show that self-piercing riveting can realize the connection between the composite plate and AA5052 aluminum alloy, and the variation of impact force with displacement is different at various impact energies and times. The higher the impact energy, the deeper the damage to the joint. At 5 J, the impact times have no significant effect on the residual strength, while at 10 J and 15 J, the residual strength decreases with the increased impact times. The failures are all manifested by tearing the lower panel of the composite plate and the rivet head is pulled out from the composite plate, and the impacts do not affect the tensile failure forms of the joints. The aluminum alloy panel shows a ductile fracture, and mixed damage occurs for the adhesive layer.