New method for determining <i>P</i>‐<i>S</i>‐<i>N</i> curves in terms of equivalent fatigue lives

Abstract

Abstract A new method for determining the P ‐ S ‐ N curves is proposed by the probabilistic analysis of the mixed samples that are composed of the testing fatigue lives and equivalent fatigue lives. The equivalent fatigue lives at each level are converted from all the testing data at all the testing levels according to the equivalent fatigue failure probability, where the life distributions are determined by the medians of logarithmic fatigue lives at respective levels and a unified coefficient of variation. Comparison results of the P ‐ S ‐ N curves of 2024‐T3 and A356.0‐T6 alloys with the different methods indicate that the new method can determine the high‐precision P ‐ S ‐ N curves with different sample sizes of the S ‐ N testing data, and can save testing time and improve testing efficiency, especially for the situation of large‐scatter S ‐ N testing data.