Effect of fitting tolerance on mechanical performance of CFRP/Al double-lap blind riveted joints.

Blind rivets are widely used in connecting composite materials. However, due to the anisotropic properties, as well as the complex failure modes of the composite materials, it is difficult to optimize the joint design of the riveted joint. This paper aims to study the effect of the fitting tolerance on the mechanical performance of CFRP/Al double-lap blind riveted joints by experiment and numerical simulation. The simulation model of an integrated blind rivet was employed to investigate the effect of installation speed and interferences on the riveting strength. Then, the tensile tests and corresponding numerical simulations for the riveted joint were conducted. Additionally, the exponential damage evolution rule for CFRP damage initiation and material stiffness degradation was used to analyze the evolution of CFRP damages during the rivet installation and the failure modes of the riveted joint under tensile loads. The simulation results of the riveting installation show that high-speed installation with interference-fit conditions can effectively reduce the resistance during installation. From the experimental results of the tensile tests, the interference-fit condition significantly improves the mechanical performance of the rivet joints compared with the clearance-fit condition. The ultimate load of the riveted joint reaches 9.93 kN at an interference percentage of 0.42%, which increases by 17.5% compared to the load at a clearance percentage of -4.2%. The simulation results agree with the experimental results, and the error rate is less than 10%.