基于功率谱密度的疲劳寿命估算

A Approach Based on Power Spectral Density for Fatigue Life Estimation

利用随机振动理论、强度理论和Miner线性累积损伤模型,获得窄带随机振动下基于功率谱密度(P.S.D)的构件疲劳寿命估算公式。根据P.H.Wirsching对不同P.S.D形状修正结果以及Dirlik的经验估计方法,建立了适用于宽带随机振动构件的疲劳寿命估算公式。该寿命估算公式不需要对变幅应力进行循环计数。讨论了局部危险部位应力功率谱密度获取的常用方法。研究了用经验方法确定构件的p s N曲线。用寿命估算公式对某构件进行了寿命预测。

Based on the information of the power spectral density(PSD), the calculation method for predicting fatigue life of components under narrow band random vibration is proposed by using random vibration theory, strength theory and Miner cumulative damage mode. The calculation method can be also coped with wide band random vibration according to the modified result of PSD and experimental methods. The life prediction method has the advantag of convenience to use and does not perform cycle counting. Power spectral density of local critical position are discussed. Experimental p-s-Ncurves are presented. The utility of the associated methodology is demonstrated by application example.