Stress Analysis and Strength Evaluation of Single-Lap Band Adhesive Joints Subjected to External Bending Moments

Abstract

The stresses in single-lap band adhesive joints of similar adherends subjected to external bending moments are analyzed as a three-body contact problem by using a two-dimensional theory of elasticity (plain strain state). In the analysis, the upper and lower adherends and the adhesive bonds which are bonded at two regions are replaced by finite strips, respectively. In the numerical calculations, the effects of the ratio of Young’s moduli of the adherends to that of the adhesives, the ratio of the adherend thickness to that of the adhesive bonds and the ratio of the bonding length to the total lap length on the stress distributions at the interfaces are examined. A method for estimating the joint strength is proposed using the interface stress and strain obtained by the analysis. Experiments to measure strains and rupture strength are carried out. A fairly good agreement is found between the estimated and the experimental results. For verification of the analysis, a finite element analysis (FEA) is also conducted. The results show that the strength of a single-lap band adhesive joint is almost the same as that of a single-lap adhesive joint in which the two adherends are completely bonded at the interfaces. Thus, the single-lap band adhesive joints are shown to be useful in the design of single-lap joints.