【作者】 杨博；

【导师】 谢伟平；

【作者基本信息】 武汉理工大学 ， 结构工程， 2004， 硕士

【摘要】 随着我国轨道交通的不断发展，列车运行速度不断提高，轨道系统振动的强度也随之增加，从而加速了轨道系统的变形和破坏。轨道振动是导致轨道失效的主要原因，高速铁路对轨道的性能提出了更高的要求，因此需要对轨道系统的动力特性有更深入更全面的了解。轨道结构是一个非常复杂的结构，一般由铁轨、扣件、枕木、碎石垫层组成，利用模态分析技术建立轨道结构动力学模型并辨识其参数是一条有效的途径为此，本文在模态分析理论的基础上主要研究了以下几个方面的内容： 1、研究振动系统的物理参数模型、模态参数模型和非参数模型的关系，即三种模型的理论建模问题。对粘性比例阻尼与一般粘性阻尼两种情况分别进行了多自由度系统的实模态与复模态分析。该部分是全文的理论基础。 2、以第二章的模态分析理论为基础，用ANSYS模拟了几种轨道模型，对建立的模型分别施加冲击荷载，简谐荷载和移动荷载，然后对得到的时域响应进行FFT变换，采用半功率法结合MATLAB编程，识别出几种模型的频率、阻尼和振型，并和理论计算结果进行了比较，得到了较满意的识别结果。这些结果对采用精确的频域法识别轨道模态参数具有很现实的意义。 3、首次将特征系统实现算法(ERA)引入轨道结构参数识别的研究中，详细推导了该方法的基本理论过程，用ANSYS建立了二维和三维轨道模型，采用MIMO的方法得到轨道模型的多点脉冲响应，构造hankel矩阵，结合MATLAB编程，识别出频率和阻尼比，并和理论计算值进行了对比，得到一些有用的结论。从结论中可以看出，该方法对轨道结构模态耦合密集的情况识别效果好，从而证明了运用该方法识别轨道模态参数的可行性。 最后，在全面总结论文工作的基础上，提出本课题尚待深入研究的若干问题。更多还原

【Abstract】 With the development of track traffic, the deformation and destruction of track system is speeded up consequently. The major reason of track invalidation is the track vibration. Due to the higher demand of track capability, it is needed to search the dynamic characteristic of track system. In general the track structure consists of track, rail pad, sleeper and ballast and it is a very complex structure. It will be a valid method to constitute track structure dynamic modal and identify the modal parameters by modal analysis technology. Therefore based on modal analysis theory, the main ideas of this paper can be summarized as follows:1 The relations of physical parameter model, modal parameter model and non-parameter-model in vibration system have been researched. That s the problem of theoretic modeling of the three models. The real modal analysis and complex modal analysis are respectively applied to the multi-degree-of -freedom system according to the different damp. This chapter is the theory basis of the paper.2 Based on modal analysis theory of chapter two, several track models are simulated by ANSYS and the impact load, harmonic load and moving load are respectively put on the models. Then the time domain responses are transferred to the frequency domain by the FFT. Final, frequency, damp and mode shape of the several models are identified by half power method and MATLAB procedure. The identification results are compared with theory results, and the satisfied results have been got.3 The Eigensystem Realization Algorithm (ERA) is first applied to identify modal parameters of track structure in this paper. Then the basis theory process of this method has been deduced. The two-dimension track model and three-dimension track model are set up using ANSYS. After the several impulse responses are got by MIMO method. The frequency and damp ratio are estimated by constructing Hankel matrix and MATLAB procedure. Finally the identification results are compared with theory results, some useful conclusions have been got. From the results, we find out that this method is applicable to estimate the coupled-modes of railway system, therefore it is feasible to identify modal parameters of track by this method.In the end, the content of this paper has been summarized and some problems, which need further study, have been proposed.更多还原