车辆-桥梁耦合系统垂向振动的随机分析

研究车桥耦合系统在轨道高低不平顺激励下的垂向平稳随机振动。车辆采用二系悬挂6个自由度的4轴客车空间模型,桥梁采用空间梁单元模型,轨道不平顺假设为多点异相位平稳随机激励。采用虚拟激励法将轨道不平顺转化为一系列的简谐荷载形式。运用分离迭代法求解车桥耦合系统振动方程。分别采用虚拟激励法和Monte Carlo法对单跨33.3m简支梁进行随机振动分析,验证了方法的正确性。最后,以1列火车通过单跨33.3m简支梁为例,研究了车桥时变耦合系统的垂向随机动力特性。

STOCHASTIC ANALYSIS OF TRAIN-BRIDGE TIME-VARYING VERTICAL SYSTEM

A new method for a vertical stationary random vibration analysis of vehicle-bridge systems subjected to track vertical profile irregularity excitations is proposed.The vehicle is modeled as a four-wheel mass-spring-damper system with two layers of suspension systems possessing 6 degrees of freedom.The bridge is modeled as a space beam,and the track irregularity is assumed to be a uniformly modulated evolutionary random process with the phase-lags between the wheels taken into account.Pseudo-excitation method（PEM）is applied to transform the random surface roughness of the track into the superposition of a series of deterministic pseudo harmonic surface unevenness.Discrete iteration is applied in the solution of equation.Numerical examples are given.Comparisons with the Monte Carlo simulations show the effectiveness and satisfactory accuracy of the proposed method.Stochastic vertical analysis has been done on a simply-supported beam when trains running on it.