Influence of boundary conditions on stress distributions in a single-lap adhesively bonded joint

Increasing applications of adhesively bonded joints require understanding of the stress distribution along the bond-line and the stresses that are responsible for the joint failure. The effect of boundary conditions on the actual stress distributions of a single-lap adhesively bonded joint was investigated using the three dimensional finite element method. Specifically, finite element solutions of the stress distributions in the adhesive layer have been obtained for three typical boundary conditions. The results indicate that though the stress distributions of a single-lap adhesively bonded joint are strongly affected by the boundary conditions of the joint, the stress concentrations are confined to a very small region near (or at) the free ends of interfaces between the adherend and the adhesive layer while the centre region of the adhesive layer is mostly stress-free. Thus, the load-bearing capability of a single-lap adhesively bonded joint may not be significantly reduced by the existence of bubbles within the bulk of the adhesive which is an important problem in actual mass production.