基于概率功能度量的疲劳可靠寿命分析方法

Reliable Fatigue Life Analysis Method Based on Probabilistic Performance Measure

在分析疲劳寿命工程常用预计方法的基础上,引入功能度量法,建立疲劳可靠寿命模型,提出可靠寿命计算、灵敏度分析方法。该方法将可靠寿命的计算问题转换为一个球面约束的优化问题,只需进行一次概率功能度量的求解即可获得可靠寿命;利用计算过程的中间量,导出了可靠寿命对随机变量均值、标准差以及确定量的灵敏度计算公式。通过对某型车辆扭力轴的可靠寿命分析,证明基于概率功能度量的疲劳可靠寿命预计方法具有较好的效率和精度,灵敏度结果有效地反映出各变量对疲劳可靠寿命的影响程度。

Based on the frequently-used engineering methods for fatigue life prediction and the performance measure approach,a reliable fatigue life model is built,and a set of methods for reliable life prediction and sensitivity analysis are proposed. By expressing fatigue life as the function of random variables,the reliable life prediction problem is converted into a spherical constraint optimization problem which can be solved using performance measure approach,and then the reliable life can be gotten directly. Moreover,the sensitivity factors for each random variable and deterministic variable can be calculated by using some intermediate variables in life prediction. The proposed method is demonstrated with a torsion shaft example. The results show that the proposed method has high efficiency and precision,and the different parameters have much different influences on reliable life.