【作者】 卜研；

【导师】 王开和；

【作者基本信息】 天津科技大学 ， 机械设计及理论， 2006， 硕士

【摘要】 工作模态分析方法是一种新的模态分析技术，利用工作状态或环境激励下的响应信号识别出的工作模态参数符合实际工况及边界条件，能真实的反映结构在工作状态下的动力学特性。本文以一供水管道系统试验台为研究对象，通过它来模拟高层楼的供水系统，针对以水泵为周期性动力源的情况进行工作模态参数识别的研究，发展了模态分析理论和模态参数辨识方法，扩展了工作模态在实际中的应用范围。 本文首先对供水管道系统工作状态下的振动、噪声信号进行了测试和频谱分析，了解了信号的频率成分，为单独利用振动响应数据进行工作模态分析提供理论依据。然后，运用试验模态分析技术和有限元分析方法相结合，研究供水管道系统的动态特性，得出管道系统的真实固有频率和振型，为工作模态分析的研究提供参照。 本文对工作模态分析的理论与方法进行了详细的推导和阐述，介绍了工作振型与模态振型的不同之处，对工作模态分析ODS FRF方法的理论进行了推导，得出在激励满足白噪声的假设条件下，可以通过拟合ODS FRF得出系统的工作模态参数。 最后，本文对供水系统实验模型进行工作模态分析，得出了系统的频域ODS和工作模态参数。利用带阻滤波对供水系统正常运转情况下的谐波激励响应信号进行预处理和采集，使信号满足白噪声激励条件；生成ODS FRF函数，并拟合得到系统的工作模态参数和振型。与试验模态结果相对比，证实了工作模态分析理论与方法的可行性。更多还原

【Abstract】 Operating modal analysis is a new technology of modal analysis. The operating modal parameters obtained only by responses of operating machinery or ambient excitation accord with the real operating situations and the boundary conditions, and illustrate the real dynamic behavior of the operating machine. This paper simulates the water supply system of high building with an experimental model of piping system, studies the theory and methods of identification of operating modal parameter with the periodic excitation.Firstly, the vibration and noise signals of the water supply piping system in the operating state are detected and analyzed, and the frequency spectnims of the signals are got, wich provides the theoretic base to operating modal analysis only using the response datas. Based on the experimental modal analysis and finite element analysis, the modal paramenters, such as the modal frequencies and mode shapes, of the pipeline system are obtained experimentally and numerically, which can be regarded as the reference of operating modal analysis.This paper presents the theory and method of operating modal analysis, introduces the difference between operating shape and modal shape, deduces the ODS FRF measurement of operating modal analysis, and draws the conclusion: if the excitation force spectrum can be assumed to be relatively flat over in the frequency range of the modes of interest, men ODS FRFs can be curve fitted to obtain the operating modal parameters.Based on the operating modal analysis of the experimental model of piping system, the frequency domain ODS and the operating modal parameters are obtained. And to satisfy with the condition of white noise excitation, the responses are preprocessed with the technology of band stop filter. The operating modal parameters are obtained and shapes are got by curve fitting the ODS FRFs generated. Compared with the results of experimental mode, it proves that the theory and methods of operating modal analysis are practicable.更多还原