非高斯随机振动下包装件时变振动可靠性分析

包装件在流通过程中经常受到非高斯随机振动激励的作用,提出了一种包装件在非高斯随机振动激励条件下的时变可靠性的分析方法。结合多项式混沌扩展和Karhunen-Loeve扩展,提出了基于功率谱(或自相关函数)、均值、方差、偏斜度和峭度信息的非高斯随机振动激励的模拟方法;为减小数值分析量,应用拟蒙特卡洛法,在随机变量空间中合理控制变量的分布模拟非高斯随机振动激励,通过四阶龙格库塔法分析,用较少的随机振动模拟样本准确得到了包装件加速度响应的前四阶矩和自相关函数。基于响应的统计信息,应用该研究提出的多项式混沌扩展、Karhunen-Loeve扩展和拟蒙特卡洛分析,获得包装件加速度响应样本,计算包装件的时变可靠性,用原始蒙特卡洛法验证了计算的准确性;该方法在包装件的可靠性分析、包装系统优化等方面具有重要意义。

Time-dependent reliability analysis of package under non-Gaussian excitation

In the process of distribution, the package is often excited by non-Gaussian excitation.In this paper, a methodology was proposed for accurate simulation of non-Gaussian excitation as well as the efficient analysis of time-dependent reliability of packages.The non-Gaussian excitation was simulated based on the first four moments of the input, i.e.the mean, variance, skewness, kurtosis and the PSD (or autocorrelation) using the polynomial chaos expansion and the Karhunen-Loeve expansion.In order to analyze the package reliability in an efficient way, the quasi Monte Carlo method was adopted, in which, the random variables were reasonably selected in random variable space to simulate non-Gaussian excitation, the acceleration response of package was obtained using the 4th  Runge-Kutta method.The accurate statistical information of the first four moments and the autocorrelation can be obtained by reduced number of simulation.Based on the moments and autocorrelation of the acceleration response, the proposed polynomial chaos expansion, the Karhunen-Loeve expansion and the quasi Monte Carlo method were used to simulate the package response.the time dependent reliability of package was analyzed and the analysis was verified by crude Monte Carlo simulation.The proposed non-Gaussian vibration simulation method and package reliability analysis method can provide theoretical basis for package analysis and packaging design optimization.