798. 複数表面欠陥からの疲労亀裂伝播挙動評価法,(I)

Many studies on the growth of multiple surface cracks have been performed for the reason that this subject is of practical importance in assessing the fatigue life of structural components with flaws. However, the effect of the front free surface and the effect of interaction of multiple surface cracks on the fatigue crack growth behavior are not clear enough. In this study, the flat plate specimens of Type 304L stainless steel with multiple surface cracks were used to investigate experimentally these effects.The empirical expressions on these effects were obtained from the fatigue test results and a method for evaluating the growth of multiple surface cracks is proposed based on these expressions. The crack growth behaviors obtained from the fatigue test were compared with the analytical results predicted by three methods, in which the proposed method is included.