Effect of Top Sheet Materials on Joint Performance of Self-Piercing Riveting

Abstract

Three types of self-piercing riveting (SPR) joints, i.e., steel/aluminum, carbon fiber reinforced polymer (CFRP)/ aluminum, and aluminum/aluminum, were constructed using three different top sheet materials with the same aluminum alloy as the bottom sheet. The effects of the top sheet material on the joint quality and mechanical behavior were evaluated. The top sheet materials’ characteristics dominate the rivet piercing process and the consequent interlock distance. The high-strength steel top sheet requires a comparatively higher rivet setting force and induces early flaring of the rivet tail, resulting in a larger interlock distance. Though the CFRP needs the highest rivet setting force to penetrate the rivet through the CFRP fibers, the CFRP/aluminum joint exhibits the smallest interlock distance because of the SPR process-induced damages to the CFRP and subsequently less flaring of the rivet tail. In strength tests, the damaged CFRP sheet resulted in rivet head pullout of the CFRP/aluminum joints, which exhibited the lowest lap-shear and cross-tension strengths. In contrast, the steel/aluminum joints demonstrated the highest strengths because of their comparatively larger interlock distances. In addition to the experimental analysis, simulations revealed the rivet penetration and flaring mechanisms with various top sheet materials, and their respective joint quality and strengths.

Steel Sheet Deformation in Clinch-Riveting Joining Process

“…It is possible to combine composites with metallic materials, with certain limitations. When a composite is the upper layer and a metal is the lower layer, for some arrangements, "SPR" [35][36][37][38], clinching [39][40][41][42][43], or solid self-piercing rivet-ing [39,44] joints can be formed. There are an increasing number of industrial applications that involve the joining of composite elements using the above-mentioned pressure joining techniques [41,45].…”

Forming Quality and Microstructure Evolution of AA6061‐T6 Aluminum Alloy Joint during Flow Drill Screwing Process

“…In recent years, lightweight materials, such as ultrahigh-strength steel, aluminum alloy, magnesium alloy, and carbon fiberreinforced composite materials, are widely used by automotive manufacturers. [1][2][3][4][5] Increasing the use of high-specific-strength alloys and maintaining the structural stiffness at the same time are concerned in achieving automotive lightweight. [6][7][8][9] Currently, self-piercing riveting (SPR) is the most common process to connect these high-specific-strength alloys and is widely used in the connection of car body materials.…”

Effectiveness of Using Low‐Strength‐Grade Filler Wires for 800 MPa Grade Ultra‐High‐Strength Steels Laser Beam Welds

“…Accordingly, the use of ultra-high-strength steels (UHSSs) with tensile strengths >800 MPa is rapidly increasing. [1][2][3][4][5] A viable welding process that utilizes UHSSs is required to assemble car bodies. Specifically, compared with conventional fusion welding, laser beam welding (LBW), which has a high welding speed and low heat input, can improve the mechanical properties of the weld joints by refining the microstructure and minimizing the size of the heat-affected zone (HAZ).…”