Abstract：The effective stress model for predicting the fatigue life distribution of notched specimens from fatigue life test data of smooth specimens is developed in this paper. In this model, the possible crack initiation surface of the notched specimen is separated into many elements and the surface is considered as a series model of these elements. Thus, according to the series failure model, the fatigue strength failure probability of the notched specimen can be calculated from that of the elements, which can be determined from the fatigue strength failure probability of the smooth specimen by using the weakest-link theory. In the formula of the notched specimen fatigue strength failure probability, the parameter of effective stress is introduced. Employing this parameter to refer to the fatigue life test data of smooth specimens would lead to the fatigue life distribution of notched specimens. This model reflects the influence of both stress gradient and component size on the notched specimen fatigue life distribution. An example of centre hole notched LY12CZ specimens was accomplished. The predicted result is in good agreement with the test result, which shows that this method is effective and practical.
2013, Vol. 34 
