Research in failure behaviors of hybrid single lap aluminum-CFRP (plain woven) joints

In this paper, the failure behaviors of the hybrid joint (HJ) of plain woven carbon fiber reinforced plastic (CFRP) and aluminum alloy were systematically studied by quasi-static tensile experiments and a new refined simulation. Experimental results showed that the HJ failure has a typical three-stage feature: first, the bond line and the rivet share the load; and then the bond line gradually fractures; finally, the rivet bears the load alone. It is also concluded that HJs are superior to bonded joints and riveted joints in strength and energy absorption. As for the simulation model, a damage mechanics model considering shear nonlinearity and distinguishing failure modes for plain woven CFRP was constructed, added with a cohesive behavior for the bond line and a bilinear elastoplastic hardening model for the aluminum alloy substrate and the stainless steel rivet. Based on the simulation model, the three-stage feature was successfully simulated. Furthermore, the simulation results shed new light on the failure mechanisms of the HJs as well as the influences of clamping force and interference-fit on the HJ mechanical properties. In conclusion, this research helps to understand the failure behaviors and provides guidance for the design and manufacture of HJs.