西安电子科技大学学报

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一种改进的识别结构模态参数的随机子空间法

李团结1;刘伟萌1;唐雅琼1;高利强2   

  1. (1. 西安电子科技大学 机电工程学院,陕西 西安 710071;
    2. 西安理工大学 工程训练中心,陕西 西安 710048)
  • 收稿日期:2016-12-09 出版日期:2017-12-20 发布日期:2018-01-18
  • 作者简介:李团结(1972-),男,教授,E-mail:tjli@mail.xidian.edu.cn
  • 基金资助:

    国家自然科学基金资助项目(51775403)

Improved stochastic subspace method for identifying structural modal parameters

LI Tuanjie1;LIU Weimeng1;TANG Yaqiong1;GAO Liqiang2   

  1. (1. School of Mechano-electronic Engineering, Xidian Univ., Xi'an 710071, China;
    2. Engineering Training Center, Xi'an Univ. of Technology, Xi'an 710048, China)
  • Received:2016-12-09 Online:2017-12-20 Published:2018-01-18

摘要:

随机子空间法可有效地从环境激励下的结构响应中获取结构的模态参数,但在识别过程中需要构造高维矩阵,对高维矩阵进行奇异值分解需要大量内存与计算时间,严重影响该算法的计算效率.针对该问题,文中通过研究协方差驱动随机子空间法中Toeplitz矩阵奇异值的分解过程,发现其中一个子矩阵对于模态参数识别结果无影响,故而提出一种新的构造Toeplitz矩阵的方法,从而降低了Toeplitz矩阵的维数,提高了计算效率.实例分析证明,改进的协方差驱动随机子空间法在保持计算精度的情况下,计算时间是原来的106%.

关键词: 随机子空间法, 计算效率, 数据驱动, 协方差, 模态参数

Abstract:

Stochastic subspace identification can be used to identify the modal parameters of a structure according to its dynamic response to ambient excitation. However, some high dimensional matrices (Toeplitz matrices) must be constructed in the process of identification, and lots of memory and computation time are cost to the singular value decomposition of these high dimensional matrixes. Stochastic subspace identification affects the computational efficiency seriously. Therefore, this paper investigates a new method for constructing lower-dimension Toeplitz matrices to improve the computing efficiency. Finally, a numerical simulation is presented to demonstrate the computing efficiency of the method. The result shows that the computing consumption of the proposed method is only 106% the computing consumption of the traditional stochastic subspace identification while the identification accuracy is maintained.

Key words: stochastic subspace identification, computing efficiency, data-driven, covariance, modal parameters

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