车辆荷载作用下简支板的振动分析

Vibration of Simple-supported Rectangular Plate to Moving Loads

应用模态综合法,建立车-桥耦合动力平衡方程,研究在车辆荷载作用下简支板的振动。采用4节点板单元建立简支板模型,用单自由度质弹系统模拟车辆。利用数值方法分别以不同的动力响应(竖向位移、纵向应力和横向应力)计算车辆荷载动力放大系数。重点分析了车速、车道位置、宽跨比及系统频比对简支板振动性能的影响。当桥梁与车辆的频率比接近1时,车-桥系统将发生共振,但不会导致振幅的无限增大。特定条件下,车辆对结构的局部冲击效应大于总体冲击效应。

Based on modal coupled method, the equations of motion of vehicle-bridge vibration were formulated. The dynamic analysis was carried out on the vibration of simple-supported rectangular plate under moving vehicle. The finite element model of the plate was set up with shell elements. And the vehicle was simulated as a SDOF spring-mass system. In this way, the dynamic amplification factors （DAF） were calculated with vertical deflection, longitudinal stress, and transverse stress. Based on the DAFs, the behavior of plate under different vehicle speeds, trajectory positions, ratios of width to span, and the ratios between the frequency of bridge and vehicle were discussed. When the frequency ratio approaches to unity, the system will experience moderate resonance. Occasionally the local impact effect due to moving vehicle on the plate may be much greater than the global one.