基于车辆响应的高速铁路周期性轨道短波病害时频特性分析

对基于同步压缩小波变换提取瞬时频率的方法进行改进,使之可完整、准确地提取振动信号的瞬时频率曲线,避免因时频聚集性较差以及交叉项的干扰带来的问题。采用该方法对高速综合检测列车轴箱加速度数据进行时频分析,提取钢轨短波不平顺的瞬时频率,根据其变化特性精确定位钢轨疑似波磨和打磨痕迹区段。结果表明:轴箱加速度波形均呈现周期性;分析区段的振动数据中包含150和75mm 2种波长呈现倍数关系的强振动数据,现场测试发现该处存在较强的钢轨波磨现象,波磨波长为150mm,同时现场还存在波长为75mm的钢轨周期性打磨痕迹;75mm的钢轨周期性打磨痕迹引起轮轨系统的非线性振动,振动频率达到1 125Hz,与扣件固有频率562Hz呈倍频关系,导致扣件产生强烈的共振,从而引发轮-轨接触共振,造成钢轨表面产生塑性变形,形成塑流性波磨,在列车的反复作用下,该处产生150mm波长的波磨。

Time-Frequency Characteristics Analysis of Periodic Short Wave Disease of Track for High-Speed Railway Based on Vehicle Response

The method for extracting the instantaneous frequency based on synchro-squeezed wavelet transform is improved to make it extract completely and accurately the instantaneous frequency curve of vibration signal,and avoid the problems caused by poor time-frequency aggregation and the interference of cross terms.This method is used to analyze the time-frequency of the axle box acceleration data of high-speed comprehensive inspection train,extract the instantaneous frequency of the short-wave irregularity of rail,and locate accurately the suspected rail corrugation and grinding trace sections according to the variation characteristics of instantaneous frequency.Results show that the acceleration waveforms of the axle box are periodic,and the vibration data of the analyzed section contains strong vibration data of 150 and 75 mm wavelengths with multiple relationships.Field test shows that there is a strong rail corrugation phenomenon.When the corrugation wavelength is 150 mm,there are periodic grinding traces of rail with a wavelength of 75 mm in the field at the same time.The periodic grinding traces of the 75 mm rail cause the nonlinear vibration of wheel-rail system.The vibration frequency reaches 1 125 Hz,which is in a frequency doubling relationship with the natural frequency of the fastener at 562 Hz.The relationship causes the fastener to generate a strong resonance,thus initiates the wheel-rail contact resonance,gives rise to the plastic deformation on the surface of rail and forms plastic flow corrugation.Under the repeated actions of trains,the corrugation with a wavelength of 150 mm on the rail surface occurs.