Fatigue and Tensile Behaviors of High Stiffness Adhesive Bonded and Hybrid Joints with Composite-Steel Dissimilar Materials

In this study, the tensile properties and fatigue behaviors of adhesively bonded and hybrid joints combining a composite and a steel were analyzed. Joint fatigue properties and failure modes were analyzed using different overlap lengths. Hybrid joints typically exhibit higher load capacities than adhesively bonded joints, because the hybrid joint generates not only the adhesive but also the fastening force of the bolt. However, in this study, the failure criterion was regarded as adhesive failure. Therefore, the hybrid joint had a lower tensile load capacity than the adhesive joint because the load sharing between the adhesive and the bolt was not occurred properly due to the high stiffness adhesive of the hybrid joint. Adhesively bonded joints exhibited increased fatigue life with increasing overlap lengths due to the increased adhesive area dispersing the load. Hybrid joints exhibited lower fatigue life due to inappropriate load sharing, caused by adhesives with relatively high stiffnesses.