结构运行状态下谐波模态的检测和去除技术研究及实现

发布时间：2017-12-31 22:09

本文关键词：结构运行状态下谐波模态的检测和去除技术研究及实现　出处：《南京航空航天大学》2012年硕士论文　论文类型：学位论文

【摘要】：在旋转机械领域，周期激励的存在产生了谐波模态，可严重影响结构运行状态模态分析的可靠性和准确度。因此，检测出谐波模态并尽可能去除其对结构模态的影响，是结构运行状态模态分析的重要内容。本文对结构运行状态下谐波模态的检测与去除进行了系统研究：丰富并完善了两种传统的时域检测方法——概率密度法和峭度法；分析了窄带滤波过程中的频带与滤波器阶次的选择对统计结果的影响；引入复频域高阶累积量的概念，提出优化谱峭度检测方法，使检测过程完全在频域进行，可实现在宽频带范围内谐波模态的同时检测，大大提高了检测效率；分析了不同运行模态参数识别算法中谐波模态引入的影响，提出谐波模态去除的必要性；研究了阻带滤波带宽的选择对谐波模态去除效果的影响，提出合适的滤波带宽选择方法；提出基于半功率谱密度矩阵的模态参数修正方法，，得出该方法易于实现且所需计算时间少；基于MATLAB GUI编程技术，开发出具有良好人机交互功能的谐波模态检测与去除软件，有助于工程应用。
[Abstract]:In the field of rotating machinery, the existence of periodic excitation produces harmonic modes, which can seriously affect the reliability and accuracy of modal analysis of structure running state. Detecting harmonic modes and removing their influence on structural modes as far as possible is an important part of modal analysis of structure running state. In this paper, the detection and removal of harmonic modes in the running state of structures are systematically studied. Two traditional time-domain detection methods, probabilistic density method and kurtosis method, are enriched and improved. The influence of frequency band and filter order on the statistical results is analyzed. By introducing the concept of high order cumulant in complex frequency domain, an optimized spectral kurtosis detection method is proposed, which makes the detection process complete in frequency domain, and can realize simultaneous detection of harmonic modes in a wide frequency band, thus greatly improving the detection efficiency. The influence of harmonic mode introduction in different operating mode parameter identification algorithms is analyzed, and the necessity of harmonic modal removal is put forward. The influence of the selection of stopband filter bandwidth on harmonic mode removal is studied, and a suitable filtering bandwidth selection method is proposed. A method of modifying modal parameters based on half-power spectral density matrix is proposed. The method is easy to realize and requires less computing time. Based on MATLAB GUI programming technology, a harmonic modal detection and removal software with good human-computer interaction is developed, which is helpful for engineering application.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH165.3

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