Shear stress analysis and optimization of dual-zone adhesive-bonded steel/Al joints

As one of the fundamental joints, adhesive joint can be applied to hybrid joints for the complex structures. To improve the material utilization of adhesive, the stress distribution of dual-zone adhesive-bonded joints was studied and optimized. Considering the elastic deformation of adhesives, the analytical models for shear stress of single- and dual-zone adhesive joint were deduced. The analytical model of single-zone adhesive joint for steel/Al was validated by FEA model and test data. Based on the analytical model, the shear stress distribution of dual-zone adhesive-bonded steel/Al joints was optimized. Results of optimization show that the stress level in dual-zone adhesive is higher than the traditional adhesive joint structure, which means the mechanical potential of adhesive can be realized better. The adhesive usage amount in dual-zone structure can be reduced 11.7% by keeping the overlapping length constant and the strength of joints not decreasing. In addition, the adhesive length close to lower stiffness material is longer than the other side which can remedy the defect of stiffness imbalance of adherends.