Mechanical properties of self-piercing riveted joints in aluminum alloy 5052

Abstract

Self-piercing riveting (SPR) is a high-speed mechanical fastening technique which is suitable for point joining advanced lightweight sheet materials. This paper reports on research into the mechanical properties of single and multiple-rivet SPR joints in aluminum alloy 5052 sheet materials. Static and fatigue tests were conducted in order to understand the effect of varying the number and distribution pattern of rivets in such joints. A statistical analysis was performed to examine the rationality of test data and the strength reliability of the joints. The failure mechanism of the joints was studied by looking at the fracture surfaces of multiple-rivet SPR joints using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) techniques. The results of mechanical experiments showed that the static strength and fatigue life of multiple-rivet SPR joints are significantly greater than for single-rivet SPR joints. Furthermore, the SEM and EDX examination results suggest that the failure characteristics are different for multiple-rivet SPR joints with the same number of rivets but different rivet distribution patterns. That the mechanical properties of the multiple-rivet SPR joints can be influenced not only by the rivet number but also rivet distribution pattern is an important conclusion. The strength and failure models are discussed and illustrated with case studies for different SPR joints.