Failure Behavior of Rivet-Bonding CFRP/CFRP Joints in Static Tension and Cyclic Tension

Abstract:

Experiments of static tension and cycle tension-tension fatigue are performed for the carbon fiber reinforced plastics （CFRP） bonding， riveting， and rivet-bonding joints. The strength and deformation behavior of the three types of joints are analyzed， the load when the joint reaches infinite cycle life is predicted， the contribution of bonding and riveting to the rivet-bonding joints is discussed， the interaction of laminate， adhesive layer， and rivet in the tensile failure process of CFRP riveted joint is analyzed， the failure mechanisms of the three types of joints under static tension and tension-tension fatigue are summarized， and three methods to improve the riveting strength are proposed. The results show that for the same CFRP laminate， it is the bonding that decides the rivet-bonding joint strength when the shear strength of adhesive is higher than that of rivet. Rivets play a role of “secondary protection” for the rivet-bonding joints. The median fatigue life of the investigated CFRP rivet-bonding joint at a static maximum load of 80%， 65%， 55%， and 45% is 8 174， 22 568， 95 014， and 331 916 times， respectively. At a load of 37.1%， the tensile fatigue life of the joint can reach 10⁶ times. Rivet hole cracking is the main failure modes of CFRP rivet and rivet-bonding joints. Adding gaskets on the riveting side and coating the surface of rivet holes can improve the riveting strength by about 30%.

Key words:carbon fiber reinforced plastics (CFRP);hybrid rivet-bonding;tension-tension fatigue;failure mode;joint strength