单车过桥下弹性车体共振与消振现象分析

为研究弹性车体振动对车桥系统动力响应影响,将车体视为两端自由的均质等截面欧拉梁、转向架及轮对视为刚体,利用模态叠加法考虑简支梁变形,用轮轨密贴接触假设建立单车通过多跨简支梁的车桥系统动力学方程,并用Newmark-β数值积分法求解系统动力响应。以一系列正弦不平顺为系统激励,研究不平顺激扰下弹性车体共振与消振现象。结果表明,弹性振动主要改变车体的振动量,对桥梁振动反馈作用较小;弹性车体共振被激发时其动力响应被显著放大,共振速度由车辆定距与车体弹性自振频率决定;因存在轴距滤波,当不平顺波长满足弹性车体消振发生条件时车体动力响应被显著抑制。

Resonance and vibration cancellation analysis of a vehicle with flexible car body moving over multi-span bridge

To investigate the effect of flexible car body vibration on the dynamic responses of vehicle-bridge system, the dynamic analysis model of a vehicle with flexible car body moving over multi-span bridges is established, and the dynamic responses of this system is computed by Newmark-β method. In this model, the car body is regarded as an Euler beam with both ends free, and the bogie and wheel set are regarded as rigid. The multi-span bridges are regarded as a series of simple bridges and the vibration of the bridges are determined by modal superposition method, and the vehicle and bridge are linked by the wheel-rail corresponding assumption. A series of irregularities are chosen as the system excitation, and the resonance and cancellation of the flexible car body are analyzed. The calculation results show that the vibration of the flexible car body has some effect on the car body dynamic responses, which shows little feedback to the bridge vibration. The flexible resonances of the car body may result in significant amplification of the dynamic responses of the car body, and the flexible resonant speeds are determined by the bogie spacing and the car body flexible natural frequencies. Due to the wheelbase filtering effect, that is when the cancellation of the flexible car body vibration occur, the dynamic responses of the car body can be effectively suppressed.