将车辆简化为两自由度移动系统,考察在不同边界条件下,实际车流作用时由桥面不平顺引发的车桥耦合系统的随机响应。运用演变随机过程的一般理论,结合状态空间理论和模态分析法,推导得出车桥耦合系统的演变随机响应。通过数值算例,对比分析不同边界条件对车桥耦合系统随机响应的影响,讨论了速度与桥面等级变化时桥梁跨中位移均方根响应的变化规律。以本文所给车列为荷载,存在一个使跨中位移均方根响应峰值突然减小的速度临界值,该临界值的大小与边界条件和桥面等级无关。
The stochastic response of the coupled vehicle-bridge system with arbitrary boundary conditions due to a vehicle queue moving on the irregular deck is studied. Combining state space theory, modal analysis and general evolutionary random processes, the evolutionary stochastic response of the coupled vehicle-bridge system is derived. According to numerical study, the effects of stochastic response of coupled system with arbitrary boundary condi- tions, the velocity of vehicle and the bridge surface roughness on the root mean square values at middle point dis- placements of the bridge are discussed. When the designated traffic flow transits bridge, there is a critical velocity, which abruptly decrease the peak value of root mean square values at middle point displacements of the bridge. And it is irrelevant to boundary condition or bridge surface roughness.