A life prediction method for size effects on notched fatigue

By use of the normalized stress distribution at the notch root of a specimen, and based on a notched fatigue life prediction method with consideration of the effects of stress gradient, a life prediction method for fatigue of notched specimen was constructed by taking mean stress, stress gradient and size effect into account with focus on the influence of size effect on the fatigue life of notched specimen. The developed method was verified by use of fatigue test data of TC4 alloy notched specimen, and the prediction results were comparatively analyzed with those of several commonly-used local stress-strain approaches, indicating that those local stress-strain approaches over-conservatively predicted the fatigue life of notched specimen. The developed method can predict the result more precisely with almost all the prediction results within the scatter band of 3 and more than three quarters of the results within the scatter band of 2.