An Analysis of Adhesive-Bonded Single-Lap Joints

Because of the technical importance and difficulty of the analysis, the present problem has been treated, as seen in the literature, by a number of authors. In the current paper a unified method is presented that has advantages in several respects for the analysis of this difficult problem and may also be employed for solving other similar problems. The method is based on two-dimensional elasticity theory in conjunction with the variational principal of complementary energy. Minimizing the energy functional leads to two coupled, fourth-order ordinary differential equations with constant coefficients for the determination of the stresses. By means of the present approach, a closed-form solution, which is adaptable for any possible adhesive layer flexibility and capable of satisfying all the boundary stress conditions of the joint, is obtained. To illustrate the application of the present unified theory, three typical examples for flexible, medium, and inflexible adhesive layers are provided and comparisons are made among these examples and with other known solutions. Special attention is given to the stress distribution in the end zones where high stress intensities of the joints occur.