基于联合加权谱密度的结构振型频域识别方法  

Model Shape Identification Method Based on Joint Weighted Spectral Density in Frequency Domain

作　　者：邹春蓉[1] 邓长军[1] 蒋伟 刘纲[3] 王惊华 ZOU Chun-rong;DENG Chang-jun;JIANG Wei;LIU Gang;WANG Jing-hua(China Railway Southwest Research Institute Co.,Ltd.,Chengdu 611731,China;Army Logistics University of PLA,Chongqing 401311,China;School of Civil Engineering,Chongqing University,Chongqing 400045,China)

机构地区：[1]中铁西南科学研究院有限公司,成都611731 [2]中国人民解放军陆军勤务学院,重庆401331 [3]重庆大学土木工程学院,重庆400045

出　　处：《科学技术与工程》2024年第32期13953-13959,共7页Science Technology and Engineering

基　　金：国家自然科学基金(52078084);重庆市自然科学基金(cstc2021jcyj-msxmX0623)。

摘　　要：针对传统加权谱密度(weighted spectral density,WSD)法中加权函数指数因子选取不当导致模态振型识别精度降低的问题,建立基于联合WSD的结构振型频域识别方法,提升了WSD方法的识别精度及适用范围。根据盲源分离与振型叠加法的相似性,采用WSD方法对结构振动信号进行解耦与分离;利用预设的多个加权密度矩阵构建三维张量加权谱,并采用平行因子2模型自适应选取加权函数指数因子;在此基础之上,引入最小谱方差评判准则进行评价,从而实现模态振型分离矩阵的精确估计。三自由度系统理论模型的模态振型识别结果表明:所提方法能准确获取各阶模态振型所对应的最优加权函数指数因子,针对结构模态振型的识别精度均优于传统频域分解法和二阶盲辨识方法,即使在数据较短、频谱毛刺严重时仍具有较高的识别精度,为建筑结构模态振型识别提供了一种新的识别算法。To cope with the shortages of low identification precision of mode shape of traditional weighted spectral density(WSD)method when select the exponential factor of weighting function inappropriately,a new mode shape identification method based on the WSD was established under frequency domain to further improve the identification precision of WSD and expand the application range.On the basis of the similarity between blind source separation method and mode superposition method,the structural vibration signal was decoupled and separated based on WSD method.An three-dimension weighted spectrum tensor was established by combine the multiple preset weighting density matrix,and the parallel factor 2 model was introduced to select the exponential factor of weighting function adaptively.Moreover,an minimum spectrum variance evaluation criteria was introduced to improve the estimation precision of separate matrix of mode shape.The identification results of mode shape of a three degree of freedom system show that the proposed method can acquire the best exponential factor of weighting function corresponding to the each mode shape of structure,and the identification precision for mode shape of system is better than traditional frequency domain decomposition method and second-order blind identification method,and it has good identification precision when the measured data length is shorter or large burrs occurs in the frequency spectrum,which provides a new identification method for mode shape of building structures.

关 键 词：模态振型识别 加权谱密度(WSD) 盲源分离 张量因子 频域法 

分 类 号：TU318[建筑科学—结构工程]