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总览 评价 芮棽 1，2， ， 费庆国 1，2，* （ 1、 东南大学工程力学系，南京，210096； 2、 江苏省工程力学分析重点实验室，南京，210096； ） 摘要： 重频现象是指多自由度结构模态频率重叠的现象，对应于该频率的结构振型是由多个线性无关的特征向量构成的
芮棽1，2，， 费庆国1，2，*
（
1、东南大学工程力学系，南京，210096； 2、江苏省工程力学分析重点实验室，南京，210096； ）
摘要：
重频现象是指多自由度结构模态频率重叠的现象，对应于该频率的结构振型是由多个线性无关的特征向量构成的振型子空间。若应变模态识别过程中不考虑结构重频的影响，则可能将重频部分的多个应变模态当成孤立模态，从而造成应变模态识别的遗漏。针对对称结构在应变模态识别过程中重频识别较难的问题，提出基于空间对称性的耦合应变模态分离方法，通过响应点位置关系分别利用对称和反对称Hankel矩阵进行识别。数值仿真结果表明，该方法可以有效分辨重频应变模态，同时提高固有频率和阻尼的识别精度。
关键词：
随机子空间；重频；应变模态；参数识别
RUI Shen1,， FEI Qing-guo12,*
（
1、Department of Engineering Mechanics, Southeast University, Nanjing, 210096； 2、Key Laboratory of Engineering Mechanics of Jiangsu Province, Nanjing, 210096； ）
Abstract：
Frequency-overlap is the phenomenon that modal frequencies are overlapped in multi-freedom structure, when the overlap modal shapes of structure corresponding to this frequency is vector subspace constituted by a few of linearly independent eigenvectors. If the influence of frequency-overlap is not considered when analyzing the strain modals, the overlap modals may be treated as an isolated modal which causes modal omission. For the problem of the strain modal identification with overlap frequencies in the symmetrical structure, the paper separates symmetric coupled strain modals through the using of the geometric relationship, thus achieving modal identification with overlap frequencies using the symmetric and antisymmetric Hankel matrix. Simulation examples show that the method successfully separated overlap frequencies of the strain modal, and increases identification accuracy of natural frequency and damping at the same time.?????
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