Stress Analysis of Bonded Plates and Joints

A general numerical method of solution for the stress analysis of adhesive-bonded stiffener plates and double joints has been developed and applied to several practical cases. The adhesive layers are treated as distributed compression-tension and shear springs. The adherends or the plate elements are considered as dissimilar elastic orthotropic plates in cylindrical bending with or without transverse shear deformations. The problem is first reduced to a system of first-order ordinary differential equations in terms of the stress resultants and the displacements of the adherends and then is solved numerically. Examples of stiffener strips bonded to a plate and also strap joint and double lap joint are chosen to illustrate the important features of the problem. It is found that the bending deformations of adherends influence considerably the stress distribution in the adhesive layer. The maximum transverse normal and shear stresses in the adhesive layer occur at the ends of the joint and they have comparable magnitudes. Therefore both stresses are most likely to contribute to the debonding failures.