【作者】 杨磊；

【导师】 林丽； 于湘涛；

【作者基本信息】 大连交通大学 ， 车辆工程（专业学位）， 2022， 硕士

【摘要】 滚动轴承是列车的关键部件,一直工作在恶劣的环境当中,长期受到交变重载的作用,极易发生故障,列车轴承故障是导致列车故障甚至引发事故的最主要原因之一。因此,针对列车轴承的故障诊断研究对保障列车行车安全具有十分重要的意义。相对于传统的滚动轴承故障诊断方法,如振动信号分析法,基于声信号的滚动轴承故障诊断法具有设备安装简单、能实现非接触式测量等诸多优势,但由于多普勒效应的影响给声信号的分析带来了困难。本文围绕现阶段轨边轴承声信号故障诊断研究中实验信号数据难以贴近实际的问题,研究多普勒效应影响下的轨边列车轴承故障声信号仿真模型的建立与分析。首先根据声源和接收处相对位置的不同,从声学和运动学两个角度分析了多普勒效应的成因,得出多普勒效应不仅与声源的相对运动有关还与声源和接收者的相对位置有关,并推导出多普勒效应影响前后的频率变化公式以及频偏率公式,为仿真模型的建立打下理论基础。再根据推导出的频率公式在Matlab中先建立了正弦信号的多普勒效应仿真模型,并且根据斯托克斯-克希霍夫公式在模型中加入了声衰减的影响使其更接近实际的声信号。最后将声源处的正弦信号替换为美国凯斯西储大学轴承故障实验数据建立了列车轴承故障声信号仿真模型,并且通过小车实验验证了该模型的正确性。在建立的列车轴承故障声信号仿真模型的基础上,研究了多普勒畸变的校正。应用了基于频偏率的等频偏重采样校正算法,根据多普勒效应的产生原理,讨论了其可行性,根据轴承故障信号的特征,通过多次试验确定了最佳的算法参数,成功校正了轴承外圈与内圈故障仿真信号,但计算时间过长。为了快速校正畸变,又提出了基于频偏率曲线的固定频偏重采样校正算法,通过仿真信号验证了其能够快速恢复频率在短时间内变化剧烈的多普勒畸变信号。更多还原

【Abstract】 Rolling bearings are the key components of trains,which have been working in the harsh environment and subjected to heavy alternating loads for a long time,and are very prone to failures,and train bearing failures are one of the most important causes of train failures and even accidents.Therefore,the research on the fault diagnosis of train bearings is of great significance to ensure the safety of train operation.Compared with the traditional rolling bearing fault diagnosis methods,such as vibration signal analysis method,the rolling bearing fault diagnosis method based on acoustic signal has many advantages such as simple installation of equipment and non-contact measurement,but the influence of Doppler effect brings difficulties to the analysis of acoustic signal.In this paper,we study the establishment and analysis of the acoustic signal simulation model of trackside train bearing fault under the influence of Doppler effect,based on the problem that the experimental signal data is not close to the actual problem in the current research of trackside bearing acoustic signal fault diagnosis.Firstly,the causes of Doppler effect were analyzed from two perspectives of acoustics and kinematics according to the different relative positions of the source and receiver,and the Doppler effect was not only related to the relative motion of the source but also related to the relative positions of the source and receiver,and the formula of frequency change before and after the Doppler effect and the formula of frequency deviation rate were derived to lay the theoretical foundation for the establishment of the simulation model.Then,according to the derived frequency equation,a simulation model of the Doppler effect on the sinusoidal signal was first established in Matlab,and the effect of acoustic attenuation was added to the model according to the Stokes-Kirschhoff formula to make it closer to the actual acoustic signal.Finally,the sinusoidal signal at the sound source is replaced by the experimental data of bearing failure at Case Western Reserve University to establish the simulation model of train bearing failure acoustic signal,and the correctness of the model is verified by car experiments.On the basis of the established simulation model of train bearing fault acoustic signal,the correction of Doppler distortion was studied.The frequency skew rate based equal frequency bias resampling correction algorithm was applied,and its feasibility was discussed based on the principle of Doppler effect generation.Based on the characteristics of the bearing fault signal,the best algorithm parameters were determined by several tests,and the bearing outer ring and inner ring fault simulation signals were successfully corrected,but the calculation time was too long.In order to correct the distortion quickly,a fixed frequency offset resampling correction algorithm based on the frequency offset rate curve is also proposed,and its ability to quickly recover the Doppler distortion signal whose frequency changes drastically in a short period of time is verified by the simulated signal.更多还原