A K_t-Based Method for Calculating LCF Life of Notched Specimens

Under cyclic loading, the effect of stress raisers on the fatigue life depends upon several parameters, the most important being the stress concentration factor, the stress level, and the material notch sensitivity. In particular, in the low-cycle fatigue region, a number of procedures are currently used, but additional developments are required for improvement of the life prediction capabilities. In this paper, a method is proposed for calculating notched specimen low-cycle fatigue life from unnotched specimen data using as the main parameter the stress concentration factor combined with the applied stress level and the cyclic-hardening properties of the material. The proposed method is then applied to several materials with a variety of notch geometries to obtain the predicted lives. The correlation between the calculated lives and the experimental data is discussed in connection with the predictions obtained from Neuber’s and Zwicky’s relations.