A VARIABLE K-F-NEUBERS RULE FOR PREDICTING FATIGUE-CRACK INITIATION LIFE

As is well known, the fatigue strength reduction factor due to a notch (K-f) in the modified Neuber's rule should not be considered a consta nt since it varies with different stress levels. In this paper, the de finition and the variation of K-f are discussed on the basis of theore tical and experimental analyses, leading to the presentation of a vari able K-f-Neuber's rule. Comparing the results of experimental stress a nalyses and the fatigue life tests of specimens, the variable K-f-Neub er's rule gives good predictions and is applied to the life prediction of an aircraft component.