A three-dimensional finite element stress analysis and strength prediction of stepped-lap adhesive joints of dissimilar adherends subjected to bending moments

Stress distributions in stepped-lap adhesive joints of dissimilar adherends subjected to bending moments are analyzed using a three-dimensional finite-element method (FEM). For establishing an optimum design method of the joints, the effects of some factors are examined. The results show that the maximum value of the maximum principal stress σ1 occurs at the butted edge of the adherend’s interfaces with higher Young’s modulus. The maximum value of σ1 increases as the Young’s modulus ratio between the dissimilar adherends and the adhesive thickness increase while it decreases as the number of steps increases. In addition, the joint strength is predicted using an elasto-plastic stress analysis. For verification of the FEM calculations, experiments were carried out to measure the strains at the interfaces and the joint strengths. Fairly good agreements were found between the numerical and the experimental results. The joint strength of dissimilar adherends was found to be smaller than that of similar adherends.