Effect of loading rate on tensile properties of GFRP/Al alloy adhesive-riveted hybrid joints

In order to investigate the effect of loading rate on the tensile properties of GFRP/Al adhesive-riveted hybrid joints, single-rivet and double-rivet adhesive-riveted hybrid joints were used as research objects, and dynamic tensile tests were conducted at loading rates of 0.5 m/s, 1.25 m/s, and 3.75 m/s, respectively. The force–displacement responses, peak force, and energy absorption indicators of the two types of joints under different loading rates were analyzed. The failure process of the joints was recorded and analyzed using digital image correlation technology, and the fracture morphology was observed by optical microscopy. The results indicate that the tensile force–displacement curve of GFRP/Al adhesive-riveted hybrid joints encompasses the overall load-bearing stage, adhesive layer failure stage, rivet load-bearing stage, and joint failure stage. The improvement of the loading rate has no significant effect on the peak force and energy absorption indicators. The average peak force and energy absorption of single-rivet adhesive-riveted hybrid joints are maintained at 3.3–3.7 kN and 13.2–13.7 J, respectively, while those of double-rivet adhesive-riveted hybrid joints are maintained at 6.2–6.4 kN and 26.6–30.4 J. In addition, the failure mode of the adhesive-riveted hybrid joints is sensitive to the loading rate. At high loading rates, the fracture and warping of the GFRP plate at the joint are the main failure modes. Meanwhile, compared with joints under low loading rates, the interlaminar failure of the GFRP plate is more severe, and the fracture shape is more regular.