• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2021, Vol. 57 ›› Issue (20): 266-276.doi: 10.3901/JME.2021.20.266

• 交叉与前沿 • 上一篇    下一篇

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基于伪频响函数矩阵法的运行模态分析方法

陈涛1,2, 褚志刚1, 李沛然2, 彭川2, 杨亮1   

  1. 1. 重庆大学机械与运载工程学院 重庆 400044;
    2. 中国汽车工程研究院股份有限公司 重庆 401122
  • 收稿日期:2021-05-29 修回日期:2021-09-24 出版日期:2021-10-20 发布日期:2021-12-15
  • 通讯作者: 褚志刚(通信作者),男,1978年出生,博士,教授,博士研究生导师。主要研究方向为振动噪声测量分析技术、声源识别技术理论及其应用。E-mail:zgchu@cqu.edu.cn
  • 作者简介:陈涛,男,1995年出生。主要研究方向为结构模态分析技术理论及应用。E-mail:ct0823@cqu.edu.cn
  • 基金资助:
    国家自然科学基金资助项目(11704040)。

Operational Modal Analysis Method Based on the Pseudo Frequency Response Function Matrix

CHEN Tao1,2, CHU Zhigang1, LI Peiran2, PENG Chuan2, YANG Liang1   

  1. 1. College of Mechanical and Vehicle Engineering, Chongqing University, Chongqing 400044;
    2. China Automotive Engineering Research Institute Corporation Limited, Chongqing 401122
  • Received:2021-05-29 Revised:2021-09-24 Online:2021-10-20 Published:2021-12-15

摘要: 基于传递率测量的伪频响函数法运行模态分析技术无需白噪声激励假设,具有强"谐波模态抑制"能力,但其模态识别结果依赖待分析伪频响函数的选取、稳定性欠佳。为解决该问题,建立了基于伪频响函数矩阵法的运行模态分析方法。该方法首先构造多参考测点、多参考工况的伪频响函数矩阵,然后基于伪频响函数矩阵采用最小二乘复频域法求解模态频率和阻尼比、基于传递率函数矩阵求解模态振型,最后通过建立相应的稳态图并结合以多参考测点平均的传递率函数矩阵第2阶奇异值的倒数为基础的模态指示函数来确定模态阶数与最终的模态结果。5自由度质量-弹簧-阻尼系统仿真结果及自由梁的运行模态试验结果均表明,提出方法既继承了基于伪频响函数法的运行模态分析方法的强"谐波模态抑制"能力,亦能有效解决伪频响函数法识别结果稳定性欠佳的问题、一定程度上提高模态识别精度,且更利于自动化。

关键词: 运行模态分析, 传递率测量, 伪频响函数矩阵, 谐波模态

Abstract: The operational modal analysis (OMA) technique based on the pseudo frequency response function (PFRF) method by the use of transmissibility measurements does not require the white noise excitation assumption, and has strong ability of harmonic modes rejection. However, its modal identification results depend on the selection of the PFRF to be analyzed, the stability needs to be improved. To solve this issue, an OMA method based on the pseudo frequency response function matrix (PFRFM) method is proposed. Firstly, the PFRFM with multiple reference measurement points and multiple reference loading conditions is constructed. Subsequently, the least squares complex frequency domain method is applied to the PFRFM to extract the modal frequencies and damping ratios, the transmissibility matrices are used to extract the modal shapes. Finally, the number of modes and the final modal results are determined by combing the stabilization diagram with the modal indicator function that is built on the arithmetic mean of the reciprocal of the second singular values about the transmissibility matrices with different references. The results of simulations for a 5 DOF mass-spring-damping system and experiments for a free beam demonstrate that the proposed method not only inherits the strong ability of harmonic modes rejection, but also can effectively solve the problem of insufficient stability of identification results of the PFRF method, obtain higher precision modal results to a certain extent, and is more conducive to automation.

Key words: operational modal analysis, transmissibility measurements, pseudo frequency response function matrix, harmonic modes

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