Riveting damage behavior and mechanical performance investigation of CFRP/CFRP thin-walled single-lap blind riveted joints

Riveting has a wide range of advantages in improving the performance of composite connections, however, it is highly likely to cause damage to the composite structure. Therefore, an experimental study was conducted to assess the damage behaviors of the carbon fiber reinforced polymer (CFRP)/CFRP blind riveted joint. Mechanical performance of joints was also evaluated experimentally. Furthermore, failure modes were exhaustively discussed. The influences of the rivet shank length on both the riveting damage and the mechanical performance were also investigated. The results demonstrated that: the surface bearing damage occurred on the first ply and was mainly caused by the pressure of forming the riveted head along the rivet shank axial. Serious damage occurred in the upper plies near the riveted head due to the radius expansion of the rivet shank. The damage modes were affected by the angles of the fiber laying direction and the rivet shank. The grooved blind riveting formed a localized protruding area around the periphery of the holes and caused less riveting damage. The failure modes of the tensile specimens were all shear failure, and the failure modes of the pull-off specimens were characterized by laminate fracture around the rivet holes, which subsequently led to rivet pull-off failure. It is worth emphasizing that the pull-off damage load and failure load of grooved blind riveted specimens were higher than those of general blind riveted specimens, while the grooved blind riveting reduced the tensile resistance.