关于航空发动机结构声疲劳寿命估算方法的探讨
Sonic Fatigue Life Prediction of Aeroengine Structure
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摘要: 噪声载荷是一种高频、宽带随机载荷,在低循环疲劳寿命预测中被广泛采用的时域计数法很难直接利用。根据现有的累积疲劳损伤理论,噪声载荷下结构疲劳寿命分析的关键在于如何在频域中获得雨流循环的概率密度函数。本文对从疲劳应力功率谱密度出发获得寿命估算所需要的应力峰值或应力雨流循环幅值的概率密度函数的方法进行了分析与比较,并对发动机结构声疲劳分析中值得深入研究及发展的方法给出了建议。Abstract: Sonic loading is a high frequency, broadband random process. Basic cycle counting methods,which are prevalently used in time domain,are difficult to be applied. According to present cumulative fatigue damage theories,the key to structure fatigue life analysis under sonic loading is to obtain the probability density function (pdf) of rainflow ranges directly form frequency domain. This paper analyzes some frequency domain approaches,which can obtain the pdf of rain-flow ranges from fatigue stress power spectral density (PSD) data. Some suggestions of promising method for aeroengine structural sonic fatigue analysis are given.
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Key words:
- aerospace propulsion system /
- sonic fatigue /
- life prediction /
- rainflow ranges /
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