Abstract: According to chemical characterization of corrosion products and theory of panel, the mathematical model is developed that correlate the amplitude of the pillowing stress of lap joints to the degree of corrosion inside the joint. Based on mathematical model, the three-dimensional(3-D)finite element(FE)model of bolted joint has been developed using the non-linear finite element code MSC Marc. More Issues such as the friction between the joint parts, and pre-stress, and material loss, and pillowing stress et al are taken into account. The results show that corrosion pillowing can significantly increase the stress in lap joint. The stress of lap joint is sensitive to pillowing stress in early corrosion or corrosion level is higher than 4%. The stress intensity factors for the crack edge along the faying surface increased as the pillowing increased while the crack edge along the outer surface decreased. In addition, the analyses show that the locations of maximum stress of lap joint will change with the material loss increasing. Simulating the effect of corrosion on lap joint only by reducing the panel thickness will result in no conservative life estimates if corrosion pillowing is ignored. The simulated results may be serving as reference for damage tolerance design of the similar structures.

Key words: Finite element method, Lap joint, Pillowing stress, Structural integrity