基于非经典阻尼模态的车辆滚摆振动分析

Sway analysis of railway vehicle based on non-classical damping mode decoupling

建立考虑车体和构架横移与侧滚自由度的车辆系统滚摆振动模型,利用复模态分解法推导系统响应公式;借助于相位同步模态分析揭示车体与构架的横移和侧滚响应与模态响应的物理关系。研究结果表明:车辆系统滚摆振动由4阶模态组成,分别为车体和构架的同相下心滚摆、同相上心滚摆、反相下心滚摆以及反相上心滚摆;轴箱外置车辆各阶模态阻尼比均比轴箱内置车辆的阻尼比大;在频率为10 Hz以内时,轴箱外置车辆的车体和构架响应明显比轴箱内置车辆的响应低,当频率为10 Hz以上时,这2种车型相差较小;当频率低于2 Hz时,这2种车型的车体响应比构架的响应大;当频率高于2 Hz时,构架响应比车体的响应大;采用合理柔性的二系横向刚度以及优化二系横向减振器阻尼,对降低车体低频振动最为有效。

A rock-roll vibrational model of railway vehicle was established taking account of the lateral displacements and the roll rotations of the carbody and the bogie frame.Formula for calculating the system response was derived based on complex mode analysis,and the physical insight between the the responses of carbody and bogie frame in lateral and rotational directions,and the mode coordinates was revealed based upon phase synchronization.The results show that there are 4 vibration modes in the sway motion of the vehicle system,including the lower sway of carbody and bogie frame in phase,the upper sway of cabody and bogie frame in phase,the lower sway of carbody and bogie frame out of phase,and the upper sway of carbody and bogie frame out of phase,respectively.The damping ratio of each mode of the vehicle with outside axlebox is larger than that of the vehicle with inner axlebox.The vibration response of the rail vehicle with outside axlebox is lower than that of the rail vehicle with inner axlebox in the frequency below 10 Hz,while above 10 Hz,the two vehicles have similar vibration levels.The vibration level of the carbody is higher than that of the bogie frame below 2 Hz,and the opposite situation occurs if the frequency is above 2 Hz for both types of railway vehicle.Adopting reasonable flexibility in the secondary lateral stiffness and the optimization of the secondary lateral damper are the most effective measures to mitigate the carbody low frequency vibration.