Fatigue behavior of single-lap adhesive joints with similar and dissimilar adherends under cyclic loading: A combined experimental and simulation study

Abstract

This study aims to research the fatigue behavior and reveal the failure mechanism of the adhesive joints with similar and dissimilar adherends, which made of the aluminum alloys (Al) and carbon fiber reinforced plastics (CFRP). Firstly, the electronic universal testing machine and fatigue testing machine were used to obtained the failure strength and fatigue life of the joints. Secondly, the joints were modeled by cyclic cohesive zone model (CCZM) to obtained the damage evolution process of the joint. Finally, the fatigue failure mechanism of the joint was analyzed based on the experimental failure mode and microscopic morphology. The results showed that in the fatigue process, the damage in CFRP-Al joints extends from the CFRP end to the Al end and eventually fractures near the Al end, while the damage in CFRP-CFRP and Al-Al joints are symmetrically distributed along the central axis of the lap area. In addition, the failure characteristics of the joints are mainly affected by the peel stress, and compared to differences in substrate stiffness (the cause of peel stress in joints with dissimilar adherends), the differences in the strength of the substrate-adhesive connection (the cause of peel stress in joints with similar adherends) plays a greater role in the generation of peel stress.