基于随机子空间法的异步实测桥梁模态识别

Asynchronously measured bridge modal identification based on stochastic subspace method

针对工程结构模态参数测试时,多个测点之间的时间不同步采样导致识别出的振型结果不准确问题,文章提出基于随机子空间法的异步实测桥梁模态识别方法,通过误差函数值表征不同步数据在分析过程中产生的数值误差程度,以误差函数为最小值时所对应的时间作为估计的时间延迟,并以此延迟修正异步实测响应数据;利用随机子空间法对修正数据进行模态参数识别,通过有限元模拟和实验验证分别讨论模态识别时,桥梁不同测点异步采样对振型识别的影响,验证所提出的时间延迟识别方法的准确性和可行性。

In order to solve the problem of the inaccurate results of identified vibration modes caused by asynchronous sampling at multiple measuring points during the testing of the modal parameters of engineering structures,asynchronously measured bridge modal identification method based on stochastic subspace method is proposed.The numerical error degree generated by asynchronous data in the analysis process is represented by the error function value,and the time corresponding to the minimum error function is taken as the estimated time delay,and the asynchronously measured response data is corrected by this delay.Stochastic subspace method is used to identify the modal parameters of the corrected data.The influence of asynchronous sampling at different measuring points of the bridge on modal identification is discussed through finite element simulation and experimental verification respectively,which verifies the accuracy and feasibility of the proposed time delay identification method.