摘要 铁路轨道的平顺状态对轮轨系统有着至关重要的影响，轨道几何形状的变化是引起车辆系统各种动态响应的主要原因。轨道不平顺是轮轨系统的激扰源，会引起机车车辆的振动和轮轨间的动作用力，对行车安全、平稳、舒适性、车辆和轨道部件的寿命以及环境噪声等都有重要影响，是轨道方面直接限制提高行车速度的主要因素；其次，轨道平顺性也是轨道结构综合性能和承载能力的重要体现，是铁路管理部门制订文修计划的重要指标。
因此，研究轨道不平顺对于保证铁路安全运营具有十分重要的理论意义和现实意义。本文在总结和吸收前人研究成果的基础上，从轨道谱和轨道不平顺的时频分析等方面对轨道不平顺进行了研究，主要研究内容如下：
1、简要分析了轨道不平顺的形成原因和影响因素，介绍了轨道不平顺的分类。在不失一般性的前提下，将轨道不平顺视为平稳的各态历经随机过程，明确了研究对象的数学模型是随机过程均匀平稳采样信号。
2、分析比较了几种评价轨道状况的方法，提出建立轨道的功率密度谱才能最有效的反映轨道状况。针对我国三大干线和郑武线高速试验段轨道谱、美国五、优级线路谱和德国高、低干扰轨道谱，利用MATLAB绘制各种轨道谱的谱线并分析比较它们之间的差异，得到了我国轨道谱的优劣与适用条件。
3、根据已有的轨道不平顺实际检测数据（京广线K80~K90区间下行线左钢轨高低不平顺检测数据（已作预处理）），运用多种功率谱估计方法，利用MATLAB编程计算，得到相应的轨道不平顺功率谱密度曲线，即轨道谱图,并对这几种谱估计方法进行分析比较，得到各种谱估计方法的优劣。
4、针对上述轨道谱图，综合线路实际条件，分析了该路段轨道不平顺的发展变化趋势，提出了一些具有针对性的养护文修意见。
5、基于美国优级线路谱，利用MATLAB编程实现轨道随机不平顺时域样本的数值模拟（逆傅氏变换法），得到轨道不平顺时域的随机样本，再将时域样本反衍，与功率谱的解析解比较，验证该方法的正确性和可靠性。关键词 轨道不平顺；随机过程；轨道谱；数值模拟
Abstract
Regularity states of the railway track have tremendous influence on the wheel-rail system, variation of track geometry is the main reason that causes dynamic reaction of the vehicle system. On the one hand, track irregularity is the excitation source to the railway vehicle system, and is the main cause of car and locomotive vibration and dynamic force of wheel-rail. It has an important influence on the transportation safety, steady, ride quality, lifecycle of vehicles and track components as well as the circumstance noise. Track irregularity is the primary factor in track aspect to limits train speed. On the other hand, condition of track irregularity indicates the synthetic performance and bearing capacity of the track structure. The condition of track irregularity is an important index for the railway administration department to advise the service plan.本文来自优.文,论,文·网原文请找腾讯324,9114
Therefore, it has important theoretical and practical value for railway safety to study on the track irregularity, Based on the recent research results, this paper focuses on two main aspects of track irregularity, which are the track spectrum and time-frequency analysis.
(1) Shortly discuss how track irregularity formed and its influent factors, after that, introduce the classification of track irregularity. In general, the track irregularities are regarded as the stationary ergodic random processes. This paper clearly considers that the math model of the study object is the uniformly sampling signal of stationary random processes.android下如何调用邮件系统
(2) After analyzing several ways to evaluate the track state, the thesis proposes that establishing the track spectrum is the most effective way to reflect the track state. According to the track spectrum of Three Main Lines and the Zheng-Wu High Speed Testing Line of our country, the fifth and sixth grade line of the US and the low and high interference line of German, each of their spectrums are drawn, their differences are analyzed and then the merits, defects and applicable conditions of our track spectrum are obtained. All these work is based on the MATLAB processing.
(3) According to the practical data of the track irregularity, utilizing the MATLAB processing and many Power Spectrum Density (PSD) assessment ways, the figures of track spectrum are got. After analyzing and comparing, the merits and defects of these spectrum assessment ways are discussed.
(4) The development trend of the track irregularity in this line is discussed according to the track spectrum figures above, suggestions of maintenance are proposed.
(5) Based on the sixth grade track spectrum of the US, the numerical modeling of track irregularity sample in time domain is implemented by the MATLAB processing using the Anti-Fourier way, and the time-domain sample is obtained. In order to test the validity and reliability of Anti-Fourier way, the time-domain sample is inversely transformed and the result is compared with the analytical solution.
Key words: Track Irregularities, Random Process, Track Spectrum, Numerical Modeling2635
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