Adhesive bonding has attracted special interest recently as a joining technique of mechanical structure. Hence, a research on estimation of fatigue strength is important to establish the design criteria for the adhesive joint.
In this study, the estimation of fatigue strength was conducted for a lap joint bounded by an epoxy-polyamide adhesive. The results of numerical analysis by FEM show that, in the case of a lap joint, the maximum tensile stress generated at the lap end well exceeds the maximum shear stress at the same location. Then, based on the assumption that the fatigue strength of the lap joint is dominated by the maximum tensile stress, the fatigue strength of the lap joint was estimated from the S-N curve of the adhesive bonded butt joint of the thin wall tube which has a uniform stress distribution.
It is confirmed that the estimated fatigue strength of the lap joint agrees well with the experimental results and, furthermore, it gives a conservative estimation.