高速列车车体抖振现象研究

针对某高速列车在运行时出现的异常抖振现象,实际测试该高速列车车体异常抖振加速度信号,将其时频特征、Sperling平稳性指标与非异常抖振加速度信号进行对比,分析发现,抖振时车体地板横向加速度信号呈现低频谐波特征,主频在10 Hz附近,Sperling指标超过"合格"限值。基于工作模态分析(OMA)并结合工作变形分析(ODS)结果识别车辆各阶模态对抖振变形的贡献量。结果表明,模态频率为9.461 Hz处的车辆模态对抖振变形贡献量最大,振型表现为车体和构架的同向蛇行运动。测试抖振车辆轴箱加速度信号和传递函数,发现轴箱受到的冲击存在时延,抖振加速度信号频率在10 Hz附近的相干性总体上优于平稳加速度信号。得出结论:轮轨接触不匹配引入的激励通过车辆悬挂系统向上传递,激起9.461 Hz处的车辆模态振动,发生抖振现象。

Study on the Chattering Phenomenon of High-speed Train Bodies

The abnormal chattering phenomenon of the high-speed train in its operation process is studied.The abnormal chatter acceleration signal of the high-speed train body is tested.Its time-frequency characteristics and Sperling stability index are compared with those of the normal chattering acceleration signals.It is found that the lateral acceleration signal of the train body floor has low-frequency harmonic characteristics during the chattering.At the main frequency around 10Hz,the Sperling index exceeds the allowable limit.Based on the OMA analysis and the ODS analysis results,the contribution of each mode to the buffeting deformation of the vehicle is identified.The results show that the vehicle mode at the modal frequency of 9.461 Hz has the largest contribution to the buffeting deformation,and the modal shows a simultaneous snake movement for train body and frame.Then,the vehicle’s axle box acceleration signal and transfer function during buffeting are tested.It is found that the shock to the axle box has a time delay.The coherence of the buffeting acceleration signal frequency around 10 Hz is generally better than the steady acceleration signal.It is concluded that the excitation introduced by the wheel-rail contact mismatch is transmitted upward through the vehicle suspension system,which stimulates the modal vibration of the train at 9.461 Hz and leads to chattering.