Comparative study of multi-range-capable rivet and standard self-piercing rivets in aluminium-aluminium and ultra-high-strength steel-aluminium assemblies

The increasing use of aluminium alloys and ultra-high-strength steels, such as CP1000, in automotive lightweight design imposes stringent requirements on mechanical joining technologies. Self-piercing riveting (SPR) is widely used in multi-material structures; however, conventional rivet systems are limited ranges of material and sheet thickness. To address this limitation, Kappe et al. introduced versatile self-piercing riveting (V-SPR), which combines an extended punch actuator with a multi-range-capable rivet to enable joining of materials with tensile strengths up to 600 MPa without tool changes. 1 This study presents a comparative investigation of a multi-range-capable rivet for V-SPR and conventional standard rivets in CP1000–aluminium and aluminium–aluminium joints. The analysis focuses on joint formation and mechanical performance under shear-tensile and cross-tensile loading. Metallographic cross-sections are used to characterise interlock formation, minimum die-side material thickness, and failure modes. Mechanical performance is evaluated using quasi-static tests, with emphasis on maximum load and failure mode. The experiments establish a demonstrated joinability matrix for the investigated sheet-thickness combinations using adapted punch and die motions. The results demonstrate the applicability of V-SPR to ultra-high-strength steel–aluminium and aluminium–aluminium joints. For the most industrially relevant combination investigated, St1.5–Al2.0 (CP1000–EN AW-6014), V-SPR achieves mechanical performance comparable to or higher than that of standard SPR while substantially reducing tool complexity through a single multi-range-capable rivet, a reduced die configuration, and fewer stack-specific changeovers. However, the independently driven inner and outer punches and active die increase actuator and control-system complexity.