强迫振动下基于快速傅里叶变换的结构模态研究

Research on Structure mode Identification base on Fast Fourier Transform Under the Forced Vibration

结构模态是工程、特别是重大工程质量和寿命全过程监控的核心研究内容。本文利用强迫振动下的振动响应数据,用快速傅里叶变换进行模态识别。本文结合有限元分析,在白噪声信号激励下对一个空间框架结构,分别利用控制理论方程求解正问题和Sap2000软件得到结构响应,继而利用快速傅里叶变换进行模态识别,并与传统广义特征值求解法对比,结果表明:二者在模态识别上具有高度的一致性。运用此方法为结构模态解析、健康损伤识别与在线监测等提供结构模态参数,具有一定的工程应用价值。

Structural modal identification is the core research about health monitoring of the whole life process for the engineering projects,especially the major engineering projects.In this paper,the fast Fourier transform theory is used to identify the structural modal though the vibration response data of the forced vibration.Based on the finite element analysis,the vibration response of a spatial frame structure is obtained by the theory of control equation or Sap2000,then the structural modal is identified though the fast Fourier transform theory,and the results shows that this method on the modal identification have high accuracy,compared with the Generalized eigenvalue decomposition method.So the engineering application value provided on this method for structural modal analysis,damage identification and online health monitoring provides the structure modal parameters.