基于运行检测的小波模态参数识别  

Wavelet-based modal parameters identification through operational measurements

作　　者：韩建刚[1] 徐晓霞[2] 任伟新[3] 

机构地区：[1]海南大学,海南海口570228 [2]福州大学,福建福州350002 [3]中南大学,湖南长沙410075

出　　处：《土木工程学报》2008年第6期27-32,共6页China Civil Engineering Journal

基　　金：国家自然科学基金(50668001);海南省自然科学基金(80627)

摘　　要：众所周知结构的运行条件和实验室测试条件明显不同,在实验室中结构的特性可以较为准确的模拟,结构激励是已知的。但是对于正常使用的结构来讲,激励往往是不可测量的,同时大部分情况下是非稳态的。因此基于运行模态的结构分析方法被提了出来,并将它作为传统模态分析的一个补充方法。提出基于运行检测的小波模态参数识别技术,基于小波的模态参数识别是将信号变换到时(频域),这有利于识别结构的动态特征参数频率、阻尼和振型。给出运行情况下结构振动响应数据的小波变换的振幅和相位与特征频率及阻尼之间的关系。提出小波谱分析方法,并用它来识别结构的振型。数值模拟的例子表明,采用小波的识别方法所识别的结果与频域的峰值法和时域的随机子空间方法所识别的相符。The structural operating conditions may significantly differ from those during laboratory tests, where the structure is well known, well installed and properly excited. For structures under natural loading conditions, or excited by random forces, excitations cannot be measured and are usually non-stationary. Hence, an improved operational modal analysis is a useful complement to the traditional modal analysis approach. This paper presents the application of a new identification procedure for structural modal parameters, named the wavelet-based identification technique. The wavelet-based identification that works in time-frequency domain is used to identify the dynamic characteristics of the structural system in terms of natural frequencies, damping coefficients and modes. It is shown how the amplitude and the phase of the wavelet transform of operational vibration measurements are related to the eigenfrequencies and damping coefficients, and the wavelet-based spectrum analysis is employed to identify the mode shapes of the structure. Two examples have demonstrated that the current identification results are in accordance with those previously obtained from the peak pick method in frequency domain and the stochastic subspace identification in time domain.

关 键 词：小波 运行模态 模态识别 峰值法 随机子空间 

分 类 号：TU311.41[建筑科学—结构工程] TN911.6[电子电信—通信与信息系统]