铁路非高斯随机振动的数字模拟与包装件响应分析

目的研究铁路振动环境的非高斯特性,并分析包装件在非高斯随机振动环境条件下的响应情况。方法结合离散傅里叶变换与EARPG(1)模型,模拟了铁路随机振动信号。根据采集的数据的PSD曲线计算幅值,利用EARPG(1)模型生成了具有尖峰特征的模拟信号,计算了相位并进行了相位整体平移,根据幅值和相位,合成了所需的非高斯随机振动信号。将包装件简化为单自由度系统,分析了包装件在非高斯振动条件下的响应情况。结果铁路随机振动的峭度大于3,偏斜度为0,属于对称超高斯随机振动,提出的模型可准确模拟出铁路振动的非高斯特性,峭度和偏斜度的误差均小于3%,包装系统的固有频率、阻尼比、激励峭度对系统的响应的峭度、均方根均有较大的影响。结论通过合理地选择包装系统的固有频率和阻尼比,可有效减小系统的响应峭度和均方根,提高包装系统的可靠性。

Digital Simulation of Non-Gaussian Random Vibration of Railway and Packaging System Response Analysis

The aims of this work were to study the non-Gaussian properties of random vibration during the raiway transportation, and to analyze the response of packages excited by the non-Gaussian random vibration. A novel approach was proposed to synthesize railway non-Gaussian random vibration which incorporated discrete Fourier transform method with EARPG(1) model. The amplitude was obtained based on the PSD curves of collected data. The EARPG(1) model was used to generate spiky data, the phase was calculated and shifted. Based on the amplitude and phase, the non-Gaussian random vibration signal required was synthesized. The package was simplified to a SDOF system, and the acceleration response of the system under non-Gaussian vibration condition was analyzed. The kurtosis of railway random vibration was bigger than 3, and the skewness was 0. So the railway random vibration belonged to symmetrical super-Gaussian vibration. The model presented in this paper could simulate railway random vibration with accuracy, and both the kurtosis and skewness error were less than 3% . The simulation results indicated that the natural frequency, damping ratio and the excitation kurtosis affected the response kurtosis and RMS value. The response kurtosis and RMS value could be effectively decreased by the proper choice of natural frequency and damping ratio of package, and the reliability of package could be increased through proper packaging design.