Stress analysis of mixed-modulus single-lap adhesive bonded joints

Mixed-modulus adhesive joints can reduce the stress concentrations and improve joint strength by varying the adhesive stiffness along the overlap region. A linear elastic stress analytical model for bi-modulus adhesive joints was developed, including the adherend shear deformations. The adhesive shear stress and longitudinal normal stress in the upper adherend in the theoretical solutions were obtained and compared with the numerical solutions determined by linear elastic two-dimensional finite element analysis (FEA). The numerical experiment shows that the theoretical and the FEA results agree closely. The relevant key parameters are identified and discussed.