Failure analysis of blind riveted CFRP /steel hybrid joints with different rivet diameters and simplified modeling considering failure behavior

Abstract This study aims to investigate the effect of rivet diameters on the mechanical performance, failure behavior, and fracture characteristics of blind riveted (BR) CFRP‐CFRP (CC) and steel‐CFRP (SC) joints under shear and cross‐tension loadings. Specifically, an improved simplified model of BR (BR‐ISM) is developed to represent the mechanical performance under quasi‐static loading conditions while considering its failure behavior. The effects of different ply angles and riveting directions on the mechanical performance of the BR joints are further discussed. The results indicate that the larger rivet diameter can effectively improve the shear properties, while exhibiting a smaller effect on the cross‐tension properties. The peak force and energy absorption for the shear joint with a 6.4 mm rivet diameter are approximately 43% and 90.5% higher than those of the joint with a 4.8 mm rivet diameter. The rivet pulled‐out failure under shear loading mainly leads to fiber fracture, and rivet pulled‐out failure under cross‐tension loading mainly causes delamination failure. Compared to the ply angle, the riveting direction of CFRP to steel can significantly improve the mechanical properties of BR joints. CS joints demonstrate increases of at least 50% in peak force and 45% in energy absorption compared to SC joints. The numerical model of the BR‐ISM can accurately simulate fiber failure of BR joints, with absolute average prediction errors of 4.6% for peak force and 8.9% for energy absorption. Highlights The effect of rivet diameter on the failure behavior of CFRP/steel BR joints is studied. The damage constitutive model MAT 58 of CFRP laminate is established. An improved simplified model is developed to characterize the mechanical properties of BR joints. The effects of ply angles and riveting directions on the mechanical properties of the BR joints are discussed.