Fatigue Strength of Notched Plates

抄録

Centrally notched plates were fatigued by changing the notch shape of a hole. And the fatigue crack propagation was investigated. It is revealed that the crack propagation curve has an inflection point; that, after this point, the crack propagation rates are unified by a power function of stress intensity factors; and that the crack length where the propagation curve indicates inflection is identical regardless of the specimen shapes. On the basis of these results, the method of the prediction of fatigue life is explained by the division of the life until this inflection point and, from inflection to failure. The former is estimated from plastic strain at a notch root and the life of smooth specimens; and the latter, from integration of the fatigue crack propagation rate. And a method of the determination of inspection intervals and crack size to be detected in practical use is proposed.