基于频域法的随机振动载荷下飞机结构疲劳分析

针对飞机结构疲劳特性,提出了基于频率域信息的随机载荷历程——功率谱密度函数(Power speetraldensity,PSD)估算结构振动疲劳的一种新的计算方法。首先对结构进行频率响应计算,得到结构的传递函数;将此传递函数与输入的功率谱相乘,获得结构的应力功率谱密度;再结合材料参数,选择合适的疲劳损伤模型,利用频域方法计算结构的疲劳强度。对某型飞机机翼,采用本文方法,应用有限元分析(Finite element analysis,FEA)获得了应力响应功率谱密度函数,并对机翼在随机振动载荷下的强度特性进行了模拟与分析,给出了分析结果。

Analysis of Aircraft Structural Fatigue Under Random Vibration Loadings Based on Information in Frequency Domain

A new calculation,named the power spectral density(PSD),is proposed for estimating structural vibration fatigue.The method is based on the information of the frequency domain of random loading history.Firstly,the transfer function is obtained by calculating the frequency response of the structure.Secondly,the transfer function is multipled with the input of the power spectrum to obtain the power spectral density of the stress of the structure,and coupled with the material parameters and the appropriate damage model.The fatigue strength of the structure is caculated through frequency-domain method.Compared with some certain standards,the strength of the wing is analyzed on the stress response PSD function by finite element analysis(FEA) under random vibration loadings.