基于非平稳非高斯随机振动的航天结构疲劳寿命分析

Fatigue Life Analysis of Aerospace Structures based on Non-stationary Non-Gaussian Random Vibration

随机振动试验是考核结构疲劳强度的常用方法,通常假定振动信号符合高斯分布。实际使用中存在非平稳非高斯随机振动环境,非平稳非高斯振动中的结构疲劳寿命分析有助于试验技术的提高。通过介绍非平稳非高斯随机振动的特征和生成方法,分析了跌宕周期对非平稳非高斯信号时域波形的影响。建立典型试件的有限元模型,按照波形再现振动试验的加载方法和时域疲劳寿命分析方法,研究了峭度和跌宕周期对疲劳寿命的影响。结果表明峭度和跌宕周期对疲劳寿命有显著的影响。研究结果对于提高环境试验真实度、改善疲劳寿命试验技术具有参考意义。

Random vibration test is a usual method for structure fatigue life assessment.Vibration signal is assumed to fit the normal distribution usually.Non-stationary non-Gaussian vibration environment exists in actual use environment.Fatigue life analysis of structure in non-stationary non-Gaussian environment is conducive to improving test technique.Feature and generating method of non-stationary non-Gaussian random vibration is introduced.Effect on time domain wave shape by roll period is analysed.A typical finite element model is built,and effect of kurtosis and roll period on fatigue life is researched,according to waveform reproduction test method and time domain fatigue life analysis technique.The results show that kurtosis and roll period has significant effects on fatigue life.The research is of useful for reference to increasing authenticity of environment test,and improving technology of fatigue life test.