二阶统计量盲辨识在模态参数识别中的应用精选.pdf

第28 卷第10 期 Vol.28 No.10 工 程 力 学 2011 年 10 月 Oct. 2011 ENGINEERING MECHANICS 72 文章编号：1000-4750(2011)10-0072-06 二阶统计量盲辨识在模态参数识别中的应用 * 姚谦峰， 张晓丹 (北京交通大学土木工程建筑学院，北京 100044) 摘 要：快速、准确地识别出结构的模态参数，是结构损伤精确识别与健康监测的重要前提。该文提出一种结构 模态参数识别的新方法。该方法以盲源分离理论中基于二阶统计量的AMUSE 算法为基础，以振动系统的自由响 应或脉冲响应为分析对象，通过对数据进行Hilbert 变换增加虚拟测点，以不同时滞下数据协方差矩阵构建联合矩 阵，通过求解时滞联合矩阵的特征值问题实现对结构模态参数的识别。联合矩阵的引入克服了AMUSE 算法仅采 用两个时滞协方差矩阵所带来的不稳定性。数值算例结果表明，该文提出的方法计算简单，识别精度高，不受时 滞选择的限制，对测量白噪声不敏感，具有很好的鲁棒性。 关键词：模态参数识别；盲辨识；二阶统计量；AMUSE 算法；鲁棒性 中图分类号：O235; TN911.7 文献标志码：A APPLICATION OF SECOND-ORDER STATISTICS BLIND IDENTIFICATION ON IDENTIFYING MODAL PARAMETERS * YAO Qian-feng, ZHANG Xiao-dan (School of Civil Engineering and Architecture, Beijing Jiaotong University, Beijing 100044, China) Abstract: It is important to identify structural modal parameters in time and accurately for accurate damage identification and health monitoring of structures. A new method of identifying the structural modal parameters is developed in this paper. This method is based on the AMUSE algorithm in blind source separation theory. It considers the free responses or pulse responses of an oscillatory system as the analysis object and increased virtual measured points by using Hilbert transformation to the data. This method uses a variance covariance matrix with different time lags to build joint matrices. It realizes identifying the structural modal parameters by solving the eigen value of joint matrices with different time lags. Introducing the