The performance and influence mechanism of lap joints in carbon fiber reinforced polymer plastic/aluminum alloy hybrid structures reinforced by 3D-printed pins and adhesive bonding

To enhance CFRP-aluminum alloy thin plate joint strength, this study proposes a novel hybrid riveting method. It involves 3D-printing multi-row micro-metal rivets on aluminum substrate, embedding them into carbon fiber fabric, and co-curing via vacuum-assisted resin transfer molding to form a joint integrating mechanical interlocking and adhesive bonding. Single-factor experiments with rivet row number (0, 1, 2, 3) as the variable evaluated mechanical performance and failure mechanisms. The single-row configuration achieved 7.54 MPa lap shear strength, 650.2% and 408.7% higher than adhesive-only (1.01 MPa) and surface-treated adhesive (1.43 MPa) groups, respectively. Strength showed a non-linear trend (1 > 3 > 2), while elongation increased with row number. Failure analysis revealed interfacial debonding for rivet-free specimens and aluminum substrate fracture for riveted ones. The non-linear strength behavior stems from multi-row rivet bridging and localized bending. This technique significantly improves CFRP-aluminum bonding.