宽带随机振动应力雨流变程概率密度双Gamma分布模型  

Double Gamma distribution model for the probability density of rainflow-range of broadband random vibration stress

作　　者：王杰[1] 陈怀海[1] 郑荣慧[1] WANG Jie;CHEN Huai-hai;ZHENG Rong-hui(State Key Laboratory of Mechanics and Control for Aerospace Structures,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China)

机构地区：[1]南京航空航天大学航空航天结构力学及控制全国重点实验室,江苏南京210016

出　　处：《振动工程学报》2024年第12期2124-2131,共8页Journal of Vibration Engineering

基　　金：国家自然科学基金资助项目(12202187);江苏省卓越博士后项目。

摘　　要：提出了一种确定宽带随机振动应力谱密度(power spectral density,PSD)对应的时域雨流变程概率密度函数(probability density function,PDF)的双Gamma分布模型,并采用神经网络方法实现了模型的参数预测。给定一系列应力PSD,利用时域随机化方法生成对应的应力时间历程。运用雨流计数法统计应力时间历程的雨流变程数,计算出应力变程概率密度值。根据上述每一个应力PSD的计算结果,对所提出的应力雨流变程概率密度双Gamma分布模型进行参数拟合,得到一组对应的模型参数。利用所得数据进行神经网络模型训练,实现由给定的应力PSD直接预测出所对应的时域雨流变程PDF。将双Gamma分布模型结果与Dirlik方法结果进行了对比,并进行了疲劳寿命预测,结果表明,提出的双Gamma分布模型对宽带随机振动应力雨流变程PDF的确定更为准确。A double Gamma distribution model to determine the probability density function(PDF)of the time domain rainflowrange corresponding to the broadband random stress power spectral density(PSD)is proposed,and a neural network method is used to implement the parameter prediction of the model.A series of stress PSDs are given,and the corresponding stress time histories are generated using the time-domain randomization method.The number of rainflow-range is counted for the stress time histories using the rainflow counting method,and the stress rainflow-range probability density values are calculated.Based on the calculation results of each stress PSD mentioned above,the proposed stress rainflow-range probability density double Gamma distribution model is parametrically fitted to obtain a set of corresponding model parameters.The results of the double Gamma distribution model are compared with the Dirlik method and fatigue life prediction is carried out,and the results show that the proposed double Gamma distribution model is more accurate for determining the broadband random stress rainflow-range PDF.

关 键 词：随机振动 疲劳寿命 应力概率密度 雨流变程 神经网络 

分 类 号：O324[理学—一般力学与力学基础]