Yield design of bonded joints

This paper deals with the problem of yield design of two bodies, the adherents, joined along their common surface by a thin layer of a third material, the adhesive. Since the computation of the solution of this problem is usually very difficult, a simplified model is developed, which also permits us to facilitate the qualitative analysis of the joint behaviour and the determination of its strength. The model is obtained by considering the limit case of adhesive of zero thickness, and the general properties of this limit problem are discussed in detail. The strength of the limit interface is governed by a limit convex which can be determined on the basis of the original convex of the adhesive. It is shown that the limit convex is susceptible to an outstanding geometrical interpretation, which largely simplifies its determination and the study of its properties. Yield criteria which are isotropic or do not depend on the mean stress are explicitly considered, and some practical examples of determination of the limit convex end the paper.