A new covariance of covariance (CoC) matrix is formed from the auto/cross-correlation functions of acceleration responses of a structure under white noise ambient excitation. The components of CoC matrix are proved to be a function of modal parameters (modal frequency, mode shape and modal damping) only of the structure. Compared to the general damage identification methods of extracting modal parameters, the formulated covariance matrix contains more information, especially the higher vibration modes of structure. Using the change ratios of CoC matrix components, a method of damage identification is proposed for structures under ambient vibration based on vibration outputs only in this paper. A seven-floor frame structure is studied through numerical simulation with two steps (namely, first damage location and then damage extent identification) to demonstrate the efficiency of the proposed method.
Key words
Damage identification /
Covariance of covariance matrix /
Ambient vibration
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References
[1] 任伟新. 环境振动系统识别方法的比较分析[J]. 福州大学学报(自然科学版)，2001，29(6)：80-86.
REN Wei-xin. Comparison of system identification methods using ambient vibration measurements [J]. Journal of Fuzhou University (Natural Science), 2001, 29(6): 80-86.
[2] 王术新. 姜哲. 基于结构振动损伤识别技术的研究现状及进展[J]. 振动与冲击，2004，23(4)：99-102.
WANG Shu-xin, JIANG Zhe. Present Developing Situation and Research Advances in The Field of Structural Damage Detection [J]. Journal of Vibration and Shock, 2004, 23(4): 99-102.
[3] Lee J J, Yun C B. Damage diagnosis of steel girder bridges using ambient vibration data [J]. Engineering Structures, 2006, 28(6): 912–925.
[4] Siringoringo D M, Fujino Yozo. System identification of suspension bridge from ambient vibration response [J]. Engineering Structures, 2008, 30: 462–477.
[5] 刘宇飞, 辛克贵, 樊健生,崔定宇. 环境激励下结构模态参数识别方法综述，工程力学，2014, 31(4): 46-52.
LIU Yu-fei, XIN Ke-gui, FAN Jian-sheng, CUI Ding-yu, A Review of Structure Modal Identification Methods through Ambient Excitation [J]. Engieering Mechanics. 2014, 31(4): 46-52.
[6] 胡异丁; 李丹; 任伟新; 李子兵，基于延时随机子空间方法的非白噪声环境激励结构模态参数识别，振动与冲击，2015, 34 (8) : 71-76.
HU Yi-ding;LI Dan;REN Wei-xin;LI Zi-bing; Modal parameter identification of structures under non-white noise ambient excitations using delay-index-based stochastic subspace method [J]. 2015, 34 (8) : 71-76.
[7] 禹丹江. 土木工程结构模态参数识别—理论、实现与应用[D]．福州：福州大学，2005.
YU Dan-jiang. Modal Parameter identification of Civil Engineering Structures-Theory, Implementation and Applications [D]. Fuzhou: Fuzhou University, 2005.
[8] Li X Y, Law S S. Matrix of the Covariance of Covariance of Acceleration Responses for Damage Detection from Ambient Vibration Measurements [J]. Mechanical Systems and Signal Processing, 2010, 24(4): 945-956.
[9] Bendat J S, Piersol A G. Engineering Applications of Correlation and Spectral Analysis [M]. New York: Wiley, 1993.
[10] Li X Y, Law S S, Wang L X. Health Monitoring of in-Service Bridge Deck by Covariance of Covariance Matrix of Acceleration [J]. Applied Mechanics and Materials, 2011, 71-78: 4808-4814.
[11] Li X.Y., Wang L.X. Law S.S., Damage detection for structures under ambient vibration via covariance of covariance matrix and consistent regularization [J], Advances in Structural Engineering, 2013, Vol.16(1): 77-86.
[12] 岳艳芳. 基于动力分析的结构损伤检测方法研究[D]. 南京：东南大学，2004.
YUE Yan-fang. Research on Structural Damage Detection by Dynamic Analysis [D]. Nanjing: Southeast University, 2004.
[13] Randall J. Allemang. The Modal Assurance Criterion –Twenty Years of Use and Abuse [J]. Sound and Vibration, 2003, 37(8): 14-21.
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