冰击荷载作用下高速车辆-轨道-桥梁系统耦合振动分析

To find out the effect of the floating ice hitting bridge piers on the dynamic behavior of high-speed vehicle-track-bridge coupled system. A refined finite element model was used to simulate the process of the floating ice colliding with the bridge pier, and the ice collision loads under different ice sheet characteristics were obtained. Based on the vehicle-track-bridge dynamic interaction theory, a vehicle-track-bridge dynamics model was established that considered the impact of the floating ice. Taking a 5×32 m simply-supported bridge as a case study, the dynamic responses of the bridge structure under different ice collision loads were investigated, and the most unfavorable ice collision loads with the greatest influence on the bridge structure were obtained. Then, the dynamic responses of the bridge subsystem and vehicle subsystem when subjected to the floating ice collision loads were analyzed. Finally, the effects of the ice collision loads on the running safety of the train passing through the bridge were studied. Results showed that the thickness, collision velocity, and compressive strength of the ice sheet were key parameters for the dynamic responses of the bridge subjected to the floating ice collision loads. The lateral displacement and acceleration of the bridge mid-span and pier top increased with increases in the ice sheet thickness and compressive strength, and first increased and then decreased with an increase in the collision velocity. The effect of the ice collision loads on the dynamic response of vehicle-track-bridge system was remarkable. Under the floating ice collision loads, the lateral displacement and acceleration of the bridge subsystem increased significantly, and the main frequency of lateral acceleration in the bridge mid-span was close to the natural frequency of the bridge, which could be the vibration around the lateral natural frequency of the bridge excited by the floating ice collision loads. The lateral vibration acceleration of the car body, derailment factor, wheel rail lateral force, and wheel unloading rate were significantly increased, with rates of increase that were more than double. This indicated that the ice collision loads had significant effects on the running safety and ride comfort of high-speed trains.