Fatigue Strength of Adhesive/Rivet Combined Lap Joints

Adbesive/rivet combined bonding has attracted special interest recently as a joining technique of highstrength steel because of its high joint efficiency. In the present study, the strength characteristics of adhesive/rivet combined lap joints were investigated. To darify bonding conditions capable of improving the fatigue strength of combined joints, fatigue tests were conducted on the rivet, adhesive and adhesive/rivet combined joints with different lap widths, adhesive and rivet strengths. Furthermore, to compare fatigue crack initiation and propagation behavior of the adhesive joint with that of the combined joint, the strain changes were measured by strain gauges bonded onto the adherend plate near the lap end. The results indicate that the fatigue strength of adhesive joints can be improved through combination with rivets of nearly equal or slightly higher fatigue strength than the adhesive joint. Furthermore, we also confirmed that fatigue cracks propagate more gradually in combined joints than in adhesive joints after crack initiation.