Study on the tensile failure mechanisms of CFRP‐Al flat‐joggle‐flat bonded joints

AbstractThis paper focuses on CFRP‐Al bonded joints, experimentally investigating the effects of joint geometries, different types of adhesives, and overlap lengths on the mechanical properties of bonded joints. Digital Image Correlation (DIC) technology was used to monitor the entire tensile processes, and the deformations and fracture processes of the bonded joints were captured. The strain evolution processes of the joints were obtained through analysis, and quantitative analyses of the joint fracture surfaces were conducted. The results indicate that the special geometric shape of the Flat‐Joggle‐Flat (FJF) bonded joint reduce secondary bending effects. Additionally, the joggle section participates in load transfer, significantly enhancing the joint's mechanical performance and altering its failure mode. Joints using ductile adhesives exhibit higher tensile mechanical properties compared to those using brittle adhesives. Compared to the bearing capacity of single‐lap bonded joints with the same overlap length and adhesive, the mechanical performance improvement of FJF bonded joints using ductile adhesives is less pronounced than that of FJF bonded joints using brittle adhesives. Increasing the overlap length enhances the mechanical properties of bonded joints. This study is expected to provide a reference for the engineering application of FJF bonded joints.Highlights FJF joints have higher bearing capacities compared to single lap joints. Ductile adhesives can effectively increase the bearing capacities of joints. Increasing the overlap length can improve the bearing capacities of joints. The end and middle of the FJF joints jointly bear the load effect. The failure modes of FJF joints are different from that of single lap joints.