Abstract
Plate bonding method is one of the new tentative repair methods for fatigue cracks. So far, the extended fatigue life of crack covered with patch plates is evaluated by using Stress Intensity Factor. However, crack propagation just after bonding patch plates cannot be evaluated by the previous crack propagation analysis based on Stress Intensity Factor. In this study, the main reason of this is assumed that the residual stress before bonding patch plates is not considered in the previous analysis, the crack propagation analysis considering the effect of the residual stress before bonding patch plates was conducted. As the results of the proposed crack propagation analysis, it was clarified that in the specimen cured under unloading condition, early crack growth ratio after bonding patch plates could be evaluated by the proposed analysis. On the other hand, in the specimen cured under cyclic loading condition, since it is difficult to estimate the residual stress before bonding patch plates, early crack growth ratio after bonding patch plates could be estimated a little larger by the previous analysis.
