Research on the hybrid joining process and failure mode of laser welding and riveting on QP980 steel/CFRP

Abstract

Combining the advantages of riveting and laser welding methods, and the characteristics of stepped rivets, excellent QP980 steel/CFRP weld-rivet hybrid joint joints were obtained and the effects of different laser powers on the welded joints were investigated. It was found that this welding method can reduce the damage to CFRP by heat input and obtain joints with favorable mechanical properties with maximum tensile shear load over 10 kN. Three failure characteristics of joints with this hybrid joining process were found: failure of steel joint, failure of CFRP, and failure of both steel joint and CFRP. The stress distribution characteristics in case of CFRP failure were simulated with ABAQUS. Different heat inputs resulted in different melting amounts of steel and CFRP, and these melted materials entered the assembly gap due to thermal expansion, thus changing the load-bearing characteristics of the hybrid joint. This load-bearing structure is not just a simple riveted and welded structure, but also forms a mechanical interlocking effect.