Influence of local surface texture by tool impression on the self-piercing riveting process and the static lap shear strength

Abstract

To increase fuel efficiency and reduce emission, aluminium alloys have been increasingly used in automotive body-in-white structures for lightweighting. Due to its advantages over some of the more traditional joining technologies, self-piercing riveting (SPR) has been widely used for these lightweight structures. Research has showed that friction is a very important factor that influences both the riveting process and joint strength for SPR, but these influences have not been fully understood. In this paper, an innovative method was used to modify the local surface of the top sheet around the rivet piercing location with different impression tools (the central pin, the small ring, the medium ring and the large ring) and garnet particles to study the influence of local frictions on rivet inserting process, joint features and static lap shear strength. The results showed that the local surface textures on the aluminium sheet did not have significant influence on the rivet inserting process based on displacement-force curve analysis. The local surface textures could slightly change the joint features, especially the rivet head height, but overall this influence was not significant. The lap shear tests showed that ring impressions with garnet particles and central pin impressions on the bottom surface of the top sheet increased the static lap shear strength of the SPR joints. The results confirmed that the critical location for local friction influence on the lap shear strength was around the rivet leg piercing location.

Influence of Corrosion of Self-Piercing Riveted High Strength Aluminium Alloy Joints with Button Cracks on the Mechanical Strength

“…They confirmed that the SPR joints with material of higher surface friction had higher static lap shear strength. Further research from Li et al [13] confirmed that the critical location of friction influence on lap shear strength was between the top and bottom sheet around the tip of the punched hole in the top sheet.By studying the influence of local pin impression with garnet particles (with different ring sizes around the rivet piercing location) on static lap shear strength of SPR joints,they proved that the impression with the smallest ring and garnet particles (right around the tip of the punched hole in the top sheet) increased the lap shear strength the most and the strength increase could be up to 16%.…”

Experimental and Numerical Investigations on the Impact of Surface Conditions on Self-Piercing Riveted Joint Quality

“…It was found that the local surface modification only slightly changed the magnitudes of joint quality indicators. The same author [12] further modified the contact interface conditions between sheets using hot water washing (around 60 • C), P120 sandpaper grinding and grit blasting. The results revealed that the hot water wash and sandpaper grinding did not show a significant influence on the joint quality.…”

“…Some efforts have been made to experimentally investigate the effects of surface conditions on SPR joint quality. Surface modification methods, including coating [11], polishing, grit blasting [10], impression [12] and lubricants [13], were adopted by researchers to change the surface conditions. By altering the bottom surface texture of the top sheet with different impression tools and garnet particles, Li [10] explored the influences of the interface condition between two AA5754 sheets on SPR joint quality.…”