LZ50钢概率疲劳S-N曲线外推新方法

基于Basquin关系,提出了将中短寿命概率疲劳S N曲线合理外推到长寿命范围的疲劳极限参数法。要求外推曲线依概率平滑通过相应的概率疲劳极限点。通过对LZ50车轴钢试验数据分析,与现有直接法和2m-1指数法比较表明,本文提出的外推方法是合理的;无疲劳极限试验数据时,可采用2m-1指数法,不宜采用安全裕度过大的直接法。根据本文方法建立了LZ50钢概率疲劳外推曲线。

Reasonable Extrapolation of the Commonly Probabilistic Fatigue S-N Curves into the Long Life Regime for LZ50 Axle Steel

A so-called probabilistic fatigue limit parameter method is proposed for the extrapolation of commonly probabilistic fatigue S-N curves in the mid-short life regime into the long life regime. The extrapolated curves are required to pass through the fatigue limits on a concurrently probabilistic sense by the Basquin equation. The extrapolated effects of the method fitting the test data of LZ50 axle steel are compared with the existent 2m-1 exponent method and the direct method. It reveals that the present method works appropriately on the extrapolation, the 2m-1 exponent method approximately, and the direct method poorly. Therefore, the probabilistic fatigue S-N curves of LZ50 axle steel including the mid-short life regime and the long life regime are finally suggested by the present method.