车辆制动作用下的车辆-路面-桥梁系统随机振动分析

视车辆、路面体系和桥梁为整个系统,将车辆模拟成弹簧和阻尼器连接的多刚体,沥青路面层模拟成Kelvin模型支承的无限长梁,混凝土路面和主梁一起模拟成Euler-Bernoulli梁。应用弹性系统动力学总势能不变值原理和形成矩阵的"对号入座"法则,建立了系统的竖向运动方程;并运用协方差等效方法模拟了车轮随机输入非平稳时域模型。研究了车辆制动作用下的车辆-路面-桥梁耦合系统的振动特性。计算表明:在其他条件相同时,刹车时,混凝土路面层对应的冲击系数为沥青路面层所对应系数的1.31倍;刹车时间为0.3 s时对应的冲击系数为刹车时间0.6 s所对应的1.29倍;路面的不平状况加剧了车辆制动作用时对桥梁冲击系数的影响。

Random vibration analysis of vehicle-pavement-bridge system under vehicle braking

Vehicle, pavement and bridge were considered as an entire system. The vehicle is modeled as a multi-rigid body connected by springs and dampers, the asphalt pavement as a boundless beam on Kelvin foundation and concrete pavement together with underlaid bridge girder as a Euler-Bernoulli beam. The vertical motion equations for the system are formulated by means of the principle of total potential energy with a stationary value in elastic system dynamics and the"set-in-right-position"rule for relating matrices. The covariance equivalence method was used to establish the unsteady random input about action of vehicle wheel. The dynamic response of the coupling system of vehicle-pavement-bridge with elastic supports under the vehicle braking was studied. The results show that when all other parameters but pavement type keep unchanged, the maximum impact factor of the simply supported concrete bridge with span of 50m long and concrete concrete pavement is 1.31 times of that with the asphalt pavement. Besides, the impact factor is influenced significantly by required time during braking and the roughness of pavement surface.