基于随机子空间法的海洋平台模态特征实时提取方法研究

海洋平台结构模态特征实时提取是其结构健康监测的一项重要手段.针对传统随机子空间算法在有限测点下无法反映结构整体特征的问题,提出了一种改进的协方差驱动随机子空间模态实时提取方法.该方法基于一种新的Hankel元素重构方式,构建了结构实际空间信息与算法的相关性,并有效降低了计算矩阵的维度,从而显著提高了平台模态识别的准确度...

Modal features real-time extraction of offshore platform based on stochastic subspace method

Real-time extraction of structural modal features is an important means of structural health monitoring.Aiming at the problem of the traditional stochastic subspace algorithm being not able to reflect overall characteristics of a structure under finite measuring points,an improved covariance-driven stochastic subspace modal features real-time extraction method was proposed.Firstly,based on a new Hankel element reconstruction form,the correlation between the actual spatial information of a structure and the algorithm was constructed,and the dimension of the calculation matrix was effectively reduced to significantly improve the accuracy and efficiency of the platform modal identification.Then,the identification method and elimination criteria of false modes based on signal accumulation characteristics were further established to solve the problem of excessive false modes in the calculation of large-scale complex structure with the traditional stochastic subspace method.Finally,taking an offshore platform in Bohai Sea as an example,the response signals of the platform were calculated using the proposed method,and the results were compared with those obtained using the traditional stochastic subspace method to verify the excellent applicability and robustness of the proposed method.