Self-piercing riveting of aluminum alloy and thermoplastic composites

Abstract

In the present study, the feasibility of joining PA6-matrix thermoplastic composite panel and aluminum alloy is considered. Self-piercing riveting processes of PA6 panels, PA6 composite panels with reinforcing fibers (glass fiber and carbon fiber), and 5754 aluminum alloy sheets are systematically investigated. Macro characterizations of the appearance and transverse sections of the self-piercing riveting joints were conducted to provide more comprehensive understanding of the composite deformation during riveting process. In particular, the effect of reinforcing fibers on the composite deformation behaviors was characterized. Lap-shear testing of the self-piercing riveting joints was performed to evaluate joint strength, and characterization of the fractured joints as well as failure mechanics analysis was conducted to investigate the underlying failure mechanisms of the self-piercing riveting joints. The effects of reinforced fibers on the failure mechanisms and mechanical performance were also discussed. The results showed that self-piercing riveting is an effective technique for joining fiber reinforced thermoplastic composite panels and aluminum alloy sheets. In addition, self-piercing riveting joints with glass fiber reinforced composite failed in a bearing mode and exhibited improved joint strength compared with the PA6 matrix; while self-piercing riveting joints with carbon fiber reinforced composite exhibited slightly decreased joint strength but significantly reduced ductility, owing to the brittleness of the carbon fiber reinforced composite.