考虑车体弹性效应的铁道客车系统振动分析

Vibration Analysis of Railway Passenger Car Systems by Considering Flexible Carbody Effect

建立了铁道客车垂向振动系统数学模型。将车体看成两端自由的均质等截面欧拉梁,并考虑二系悬挂采用半主动减振器,导出客车系统的运动微分方程组,给出客车系统各模态共振速度的定义和计算公式。共振速度是车辆系统的固有属性,车体弹性振动各模态共振速度由车体的自振频率和车辆定距决定。计算车体一阶和二阶弯曲振动共振速度及对应的轨道波长,进行了客车系统在轨道简谐输入情况下的幅频特性分析和随机输入情况下的随机响应分析。通过计算可知,为了减小车体垂向共振峰值,车体一阶弯曲自振频率应尽量离开构架的浮沉自振频率;由于车体弹性振动的影响,车体端部的振动加速度和位移要大于中部,弹性车体模型的平稳性指标大于刚性车体;采用半主动减振器能够显著降低车体的加速度、位移和平稳性指标,但会使构架的加速度和位移有所增大。

The mathematical model of the vertical vibration for railway passenger car is established. The carbody is taken as an uniform Euler beam with free ends, and the semi-active damper in the secondary suspension system is taken into account. The definition of resonant speed for vehicle flexible mode vibrations and their calculation formulae are given. The resonant speed is the inherent feature of the vehicle system and is only related to natural frequency of the carbody and center distance of the bogie. The resonant speeds for the first and second vertical bending vibrations of the carbody and the corresponding wave length of the track are calculated. The harmonic and random vibration analyses of the vehicle system are carried out. The calculations show that the first bending natural frequency of the carbody should be far away from the natural frequency of vertical rigid mode of the bogie frame in order to reduce the resonance peak of the carbody. Due to flexible effect of the carbody, the acceleration and displacement at the ends of the carbody should be greater than the values in the middle of the carbody, and the ride index of the flexible carbody model be larger than the value of the rigid body model. Application of the semi-active damper can significantly reduce the acceleration, displacement and ride index of the carbody, but will increase the acceleration and displacement of the bogie frame.