【摘要】 推广虚拟激励法来研究水平地震作用时三维车桥耦合时变系统的非平稳随机振动以及最大值估计方法。水平地震动假设为均匀调制非平稳随机过程;轨道不平顺假设为多点异相位均匀调制非平稳随机激励。借助时变系统的虚拟激励法将水平地震和轨道不平顺随机激励分别转化为一系列确定性简谐激励,为了能更真实地模拟车轮作用力在时间域和空间域的连续变化,采用精细积分格式进行数值积分,得到了系统随机响应的时变功率谱密度函数和标准差。最后基于首次穿越破坏准则给出了系统非平稳随机响应的最大值估计方法。在数值算例中,通过多样本时间历程法的统计平均验证了该文随机振动分析方法的正确性和最大值估计方法的有效性;并讨论了场地土条件对系统随机响应的影响。更多还原

【Abstract】 Non-stationary random vibration and peak value estimation of 3-D train-bridge systems subjected to the action of lateral horizontal earthquake are investigated based on the pseudo-excitation method(PEM).The lateral horizontal earthquake is assumed to be a uniformly modulated non-stationary random process,while the excitations of track irregularity are assumed to be multi-phase uniformly modulated non-stationary random excitations.The pseudo-excitation method is extended and applied to transform the random excitations due to horizontal earthquake and track irregularities into a series of deterministic pseudo harmonic excitations respectively.And then the corresponding pseudo responses are solved by using the precise integration method(PIM) iteratively.By this means,various non-stationary random responses including the time-dependent PSD and RMS of interested quantities can be obtained easily.Furthermore,a new estimation method of peak value for such non-stationary random responses is suggested based on first-passage failure criteria.The effectiveness and accuracy of the proposed method are justified numerically by the time history method,and the influence of site type on random responses of the system is discussed.更多还原