本文基于疲劳可靠性的基本原理，在疲劳寿命对数正态分布的假设下，根据t分布理论，结合船舶及海洋工程一般构件具有95%置信度和97.72%可靠度下的P-S-N曲线的基本要求，推算出了具有95%置信度和误差限度5%内的疲劳试件个数与允许的最大变异系数数值对应关系，以此作为成组法疲劳试验的最少试件个数的判据开展典型节点的疲劳试验，得到具有95%置信度的百位估计值$ {N}_{p} $；并通过线性相关系数r判断对数疲劳应力Y=$ {\mathrm{log}}S $与X=$ {{\mathrm{log}}}{N}_{p} $之间线性相关的程度，采用最小二乘法对对数疲劳寿命$ {{\mathrm{lg}}}{N}_{p} $和对数疲劳应力$ {{\mathrm{lg}}S} $线性拟合，得到具有95%置信度的P-S-N曲线，并与IIW规范中相应的曲线进行对比分析，验证了本文试验方法的可行性和可靠性。
Based on the basic principle of fatigue reliability, under the assumption of lognormal distribution of fatigue life, according to the t distribution theory, and in combination with the basic requirements of P-S-N curve for ships and marine engineering general components with 95% confidence and 97.72% reliability, the corresponding relationship between the number of fatigue specimens with 95% confidence and within 5% of the error limit and the allowable maximum variation coefficient value is calculated, The fatigue test of typical nodes is carried out based on this criterion as the minimum number of test pieces in the group method fatigue test, and the Np with 95% confidence is obtained. The degree of linear correlation between fatigue stress logS and fatigue life logNp judged by the linear correlation coefficient r, and the fatigue life logNp and fatigue stress logS are linearly fitted by the least square method to obtain a P-S-N curve with 95% confidence, which is compared with the corresponding curve in the IIW , the results shows the method in this paper is feasibility and reliability.
2024,46(12): 8-12 收稿日期：2023-05-12
DOI：10.3404/j.issn.1672-7649.2024.12.002
分类号：O346.2
作者简介：张凡(1982-),女,硕士,高级工程师,研究方向为疲劳强度评估技术
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