SDB-80型转向架轮对损耗分析

针对轮轨型面磨损问题,首先,对青岛地铁3号线现有的轮对测量数据进行分析,报告了轮对存在偏磨现象且轮对镟修损耗占轮对寿命比值较大的现状。然后,对轮对异常磨耗进行研究,指出轮对缺少润滑、线路曲线分布不对称和列车长时间不掉头运行是导致轮对产生异常磨耗的主要原因。最后,根据线路实际情况,提出了采用轮缘润滑或小半径曲线外轨轨侧涂油等方式降低轮轨摩擦系数、车辆定期掉头运行和采用薄轮缘镟修的方式对轮对进行镟修等解决措施,降低轮对的损耗速率,增加轮对的使用寿命。     

轮对参数接触式检测的试验研究

介绍了近年来国内外关于铁路轮对几何参数检测的现状。提出了一种并联式伸缩机构作为传感器执行机构、定长测量臂的磁性滚轮扫描测量轮辋尺寸的接触式检测方案。分析了试验检测系统的测量原理及其误差,并用轮辋模板作了试验研究。     

Analysis of new method for vertical load measurement in the barycenter of the rail web by using FEM

Continuous method for measuring the forces between the wheel and rail is very important to monitor track loads. One of the usual methods is installing a strain gauge on the rail surface. Thus, strain gauge exposed to aggressive environment that makes it difficult for system to measure exclusively vertical force component and has complex installation operation. In this paper, strain measurement to assess the vertical load on cross section barycentric of rail and the lateral surface of rail web are studied. For this purpose, finite-element analysis was performed and the forces that exchange between wheel and rail in contact location were replaced with the moving loads that were applied to the railhead directly. Size of the effective contact patch was obtained from Hertz contact theory and patch switching time was considered short enough to reach an approximate continuous moving load. The results demonstrate the magnitude of strain in vertical direction is approximately same for the cross section barycentric and lateral surface of the rail web. However, the great advantage of measurement in the cross section barycentric of rail better distinguishes longitudinal and lateral strains from the vertical and also lateral load on a rail has less effect on vertical load measurement.     

Continuous measurement of interaction forces between wheel and rail

Oscillatory wheel load fluctuation of considerable amplitude is always observed in railway cars traveling at high speed. This paper describes a continuous method for measuring the derailment coefficient and the forces between the wheel and rail. The acceleration measured on the axle box indicates that the frequency of this fluctuation can be as high as 70 Hz. Continuous measurement of wheel load using conventional methods is not possible due to this high frequency phenomenon. We have developed a new method for continuous measurement of these forces and the derailment coefficient using two pairs of strain gauge bridges with output phases shifted by 90°, and summing their outputs with a weighting function. This method works for measuring the forces between wheel and rail at high frequencies.     

Fortpflanzung von oberflächenstörungen bei aufeinander abrollenden radial belasteten Rädern

Rolling test-rig trials were conducted in which railway wheelsets ran under normal load without slip and at constant speed upon rail profiled wheelsets. The wheelsets experienced occasional interference owing to the occurrence of periodic pitting or grooving in the running surfaces. Both mating wheels indicated an aliquant number of wear periods.Although of equal periodic length, the wear phenomena were of varying character such that they could not have been due to a reciprocal pressure process. It was demonstrated that the length and pitch of the wear periods could be explained as being due to surface wave pulses of propagation velocity c = 2950 m s^?1 circulating both wheels. Relations between wheel diameters, running speed and velocity c were formulated, under which (at adequate load application) periodic pitting or grooving could be expected to occur in the contact area. The surprising recurrence of extremely minute wear pits of less than 1 mm in size and the occurrence of pits and grooves at equidistant lateral intervals led to the assumption that, generally, interaction between acoustic emission and pitting can occur, in the course of which “coherent” ultrasonic waves are induced. On numerous occasions during test-rig trials, corrugations instead of pitting formed on one of the wheelsets and an even number of corrugations appeared on the rim. Circulating Rayleigh wave pulses seem to be involved in this phenomenon and the presence of even numbers seems to be due to a stationary surface wave on the wheel.     

磁流变耦合轮对车辆高速曲线通过性能研究和探讨

为使磁流变耦合轮对车辆向高速铁路的工程化有较大的进展,建立31自由度的车辆系统数学模型。仿真计算表明：磁流变屈服应力小于某一值和曲线半径小于一定值时,对轮对的横移、摇头、轮轨横向力和车体横向加速度造成的波动较大,有的可能会出现两点接触;屈服应力在随后的一定范围内,车辆在不同半径曲线上的以上性能参数变化平缓且较小;继续增大屈服应力,以上性能参数则增加。因此,当磁流变的屈服应力在一定范围内变化时,磁流变耦合轮对车辆才具有较好的高速曲线通过性能。     

Wayside system for wheel–rail contact forces measurements

The system for assessment of the wheel–rail contact forces can be used for multiple purposes, among them for estimation of the train running safety, for train axle load measuring or wheel flats detection, as well as for the other research analyses. As the wheel–rail rolling contact moves along the track during train motion, it is very difficult to establish a reliable and accurate system for measuring of contact forces. Measurement principle of the wayside system, presented in this paper, is based on rail strains measurements using strain gauges, connected into the Wheatstone bridges in a smart way, in order to achieve signal proportional to applied load. This principle uses independent component analysis (ICA) model in combination with system calibration for successful separation of vertical and lateral contact forces from recorded strain signals. In addition, the system provides identification of the contact point position on the rail during train passing over it, which further expands the possibilities of its application to wheel–rail wear analysis, contact geometry optimization etc.     

基于离线监督性学习的高铁轮轨关系在线检测技术

为维持高铁稳定运行,提升资源运输安全,在离线监督性学习算法的基础上,提出了一种轮轨关系在线检测技术。通过高速摄像机获取待检测图像,并进行拼接处理;计算加速度、轮轨力和轮轨间关系,依据关键部分的振动值得到列车的加速度值,以此判断列车是否处于平稳运行状态;通过间接测量法计算列车的横向力平衡方程和侧滚力矩平衡方程,得到轮轨力具体值;通过 k 均值算法聚类处理以明确各个样本的类中心,找出样本数量最少的类,设为异常类,完成高铁轮轨关系的在线检测。仿真实验结果表明,在稳定性、数据可靠性和实际应用方面,各项参数曲线变化幅度极为相同,曲线走向几乎一致,且使用后的轮轨接触状态较好,满足高铁轮轨关系在线检测技术的实际应用需求。     

Rail–wheel interaction monitoring using Acoustic Emission: A laboratory study of normal rolling signals with natural rail defects

This paper presents a laboratory study on the Acoustic Emission (AE) generated during railway wheel–rail track interaction, with a view to developing methods of in situ rail–wheel interaction monitoring using rail-mounted sensors. It is known that the physical processes of impact and wear generate AE and it was therefore expected that axle loads, speed and traction would influence the AE generated by an interaction and that the characteristics of “normal” interaction would be affected by wheel and/or track defects and/or any misalignment between rail and track.A set of laboratory experiments were carried out on a scaled test rig to characterise the continuous AE generated by a wheel rolling on a rail and, secondarily, to assess the effect on the AE characteristic of the natural defects present on the contact profile of the rail. The natural defects were of a relatively minor nature and their assessment serves as part of the calibration of background AE for experiments with more significant simulated defects.A simplified analytical model, devised for AE waves propagating from a moving source, based on “vehicle” speed and wave damping coefficients, has been developed for the test track and fitted to the measured results. As a wheel rolls towards a sensor and then away from the sensor the measured AE generally rises and falls in a predictable way. The effects of wheel and rail surface features were found to introduce deviations from this “background”, and a method to identify the location of surface defects, based on identifying peaks above the background is also demonstrated.     

Characteristics of Vibration and Sound Radiation of Metro Resilient Wheel

Resilient wheels are extensively used in urban rail transit, especially for tramway systems, owing to its advantages in noise reduction. A new type of resilient wheel for a metro is designed, and its characteristics of vibration and sound radiation, including the rolling noise of a resilient single wheel coupled with a track, are studied in this paper. A two-step research is presented. Firstly, laboratory experiments were conducted to obtain the vibration response of the designed resilient wheel under the radial excitation on its tread. Secondly, the rolling noise model of the resilient wheel coupled with a slab track used in a metro line is developed. The wheel model is based on the 3 D finite elementand boundary element methods and verified by using the experimental results obtained from the laboratory. The track vibration model is based on the wavenumber finite element method, and the track sound radiation is calculatedby using an e cient frequency-domain Rayleigh method. The interaction of the resilient wheel and the slab track is analyzed considering the measured wheel/rail roughness of the metro. The contribution of the resilient wheel to the reduction of wheel/rail system noise is analyzed. The results show that the resilient wheel can e ectively reduce the wheel/rail rolling noise by approximately 2 dB(A) to 3 dB(A), mainly because the radiated noise by the rail is reduced. In addition, the elastic modulus of the rubber has an important influence on the noise reduction of resilient wheels.     

基于轮轨法向间隙的车轮踏面优化方法

为了寻求基于目标的铁路车辆车轮踏面数值优化技术,开发一种考虑轮轨法向间隙参数的车轮踏面优化方法。利用该方法优化我国高速列车车轮LMa型面。并发现优化后的LMa车轮和CHN60钢轨滚动接触接触时,轮轨界面之间具有较好的“共形”特性,这样能有效降低轮轨接触应力以达到降低滚动接触疲劳目的。并用车辆轨道耦合动力学理论分析优化的车轮型面对车辆动态特性的影响。数值结果表明,在不降低车辆动力学性能的情况下,此方法可以有效改善轮轨接触点对分布,降低轮轨接触应力。     

曲线半径及轴重对轮轨摩擦功影响的研究

基于非Hertz滚动接触理论利用数值计算方法详细分析了静态接触情况下,轴重和曲线半径对轮轨接触质点间等效应力、接触斑粘滑区的分布、总滑动量和摩擦功的影响。分析计算表明,轴重增加引起轮轨接触质点间等效应力,接触质点间粘滑区的面积以及总滑动量的变化,同时对轮轨接触质点阍的摩擦功的变化有重要影响;小曲线半径处轮轨接触质点间的总滑动量,接触斑滑移区的面积以及摩擦功都明显增大,导致曲线上钢轨磨损加剧。因此曲线半径和轴重是影响轮轨滚动接触磨损的重要因素。     

基于车内噪声的轨道衰减率限值研究

轨道衰减率是反映钢轨动态特性的重要指标,决定了钢轨的有效声辐射长度,进一步影响轮轨噪声和车内噪声。我国地铁轨道结构型式较多,轨道衰减率也相应地并不统一,目前我国没有轨道衰减率的相关标准,现有的国际轨道衰减率标准并不能与我国车内噪声标准相对应,因此,研究轨道衰减率与车内噪声的内在关联,对基于噪声限值的轨道衰减率控制具有重要意义。首先建立轨道振动预测模型,基于现场测试对模型进行验证,并基于仿真预测分析扣件系统参数对衰减率的影响。根据有限元-边界元方法和轨道衰减率对轮轨噪声的贡献关系,建立基于轨道衰减率的轮轨噪声预测模型;根据线路试验研究,建立轮轨噪声和车内噪声的传递函数,从而采取仿真与试验联合的手段,以轮轨噪声为"桥梁",建立轨道衰减率和车内噪声的对应关系,根据车内噪声限值,量化分析基于车内噪声控制的轨道衰减率限值,确定较为优化的扣件系统参数。成果可为基于车内噪声的轨道衰减率控制,以及扣件系统参数优化设计提供参考。     

高速列车轮对磨耗统计规律及预测模型

为研究我国高速列车轮对踏面磨耗规律,对某线路服役高速动车组进行跟踪测试,记录其镟轮周期内的踏面磨耗量,并基于对磨耗统计特征的两次拟合提出轮对型面磨耗预测函数模型。对某高速线路实测型面磨耗量进行拟合,分别得到各走行里程下磨耗量关于型面位置的拟合函数;并进一步对各走行里程下的拟合函数系数进行二次拟合,得到磨耗量关于型面位置及走行里程的二元预测函数。在模型的预测精度与适用性验证时,对比相同走行里程下预测型面和实测型面在轮轨接触几何关系与车辆各关键部件加速度响应两方面结果。对比结果显示,提出的磨耗预测模型在轮轨接触点、等效锥度、轮轨作用力及车辆安全性等各方面均与线路实测结果具有很好的一致性。     

轮轨两点接触的有限元分析

在轮轨单点接触计算分析的基础上,建立锥形踏面车轮的轮缘贴靠钢轨形成两点接触的计算模型,应用有限元参数二次规划法分析这一弹塑性接触问题。对不同载荷作用下的轮轨两点接触模型分别进行计算,得出了大量的轮轨接触状态、接触力的分布及变化规律。这些计算结果将有助于找到缓解钢轨侧磨和轮缘磨耗的方法。     

城轨车辆轮对尺寸在线测量系统的研制

针对城轨车辆轮对测量费时费力的问题,基于激光轮廓扫描传感器技术,开发了一种城轨车辆轮对尺寸在线测量系统。系统采用将激光轮廓扫描仪和激光位移传感器布置在钢轨的内外两侧。将轮廓扫描仪发射的激光线投射到车轮踏面上,实时测量经过测量区域内的车轮踏面外轮廓,并对测量结果进行插值运算、数据平滑运算等算法处理,获得车辆轮对的轮缘高度、轮缘厚度、车轮直径等主要参数。通过对测量结果数据分析,该系统可以完成运行中地铁车辆轮对参数的自动测量。     

Effect of a scratch on curved rail on initiation and evolution of rail corrugation

The effect of a scratch formed on the running surface of a curved rail, due to the slide of a locomotive wheel, on the formation and evolution of rail corrugation is investigated in detail with numerical methods when a wheelset is steadily and repeatedly curving. In the calculation we consider a combination of Kalker’s rolling contact theory with non-Hertzian to be modified, a linear frictional work model and a vertical dynamics model of railway vehicle coupled with a curved track. Also the influence of different speeds of wheelset curving through the scratch on the development of the corrugation is taken into account. The numerical results indicate that a scratch causes strong contact vibration between the wheel and rail, and initiation and development of rail corrugation under the condition of steady creepage occurring between the wheel and curved rail. The wave-length of the corrugation depends on the speed of wheelset curving and the natural frequencies of the track.     

轮对几何参数在线检测系统研究

轮对作为铁路车辆重要的走行部件,对于铁路的安全运输起着关键性的作用。因此准确的检测车轮的磨耗状况是非常重要的。本文将结构光视觉传感技术应用到车辆轮对几何参数的在线测量上,完成测量系统的开发,实现在线动态测量。     

轮轨关系研究中的力学问题

简单论述世界铁路发展状况和铁路交通运输的优越性。详细论述轮轨关系的研究问题,其研究包含轮轨滚动接触作用和稳定性问题、轮轨粘着和强度、接触表面磨损和滚动接触疲劳破坏、轮轨噪声、轮轨蠕滑率／力理论和轮轨三维弹塑性滚动接触问题。在这些问题研究中,蕴涵十分复杂的力学和强度问题。文中就这方面的研究现状和存在问题以及问题研究的难点进行讨论,并分析今后可能的研究方向。     

基于Tγ/A-磨损率模型的车轮磨耗仿真分析

基于实验室获得的CL60车轮材料Tγ/A-磨损率曲线建立车轮踏面磨损模型,通过Simpack软件建立C80货车模型进行车辆轨道动力学仿真,利用Tγ/A-磨损率车轮踏面磨损模型对车轮踏面的磨耗规律进行仿真分析。结果表明：25 t轴重、600 m曲线半径工况下,同一转向架的前轮对较后轮对磨耗严重,同时与内轨处车轮相比,外轨处车轮磨耗较为严重;由于Tγ/A-磨损率曲线中磨损率输入取值的连续性,相同工况使用该模型获得的仿真结果比采用Archard磨损系数仿真得到的结果要小,其结果具有更好的精度。基于Tγ/A-磨损率的车轮踏面磨损模型为未来复杂服役环境下的车轮踏面磨耗预测提供了重要的方法。