Numerical and experimental investigation of fitting tolerance effects on bearing strength of CFRP/Al single-lap blind riveted joints

This paper deals with the effects of rivet-hole tolerance in CFRP/Al single-lap blind riveted joint by combining the experimental tests and numerical simulation approaches. The simulation model was established based on continuum damage mechanics incorporated with extended 3D failure criteria. Meanwhile, the exponential damage evolution rule of CFRP damage initiation and material stiffness degradation were applied. The inserting, locking and the corresponding tensile tests for rivet jointed with different clearances or interferences were conducted, and the corresponding simulation results were obtained and compared with experimental results. Scanning electron microscope (SEM) was used to analyze the CFRP damages during the rivet installation. X-ray scan technology was applied to observe failure forms of rivet joint after bearing tests. From the experimental and simulation results, although interference-fit joint can induce the material damages around the hole in insertion process, improved bearing strength for CFRP/Al single-lap blind riveted joint can be obtained comparing with clearance fit conditions. In addition, the evolution of CFRP damages during the rivet installation and failure forms of rivet joint under tensile loads were investigated.