[1] Li Shu, Xu Zhaodong, Wang Shaojie, et al. Modal macro-strain identification from operationalmacro-strain shape under changing loading conditions [J]. Journal of Southeast University (English Edition), 2016, 32 (2): 219-225. [doi:10.3969/j.issn.1003-7985.2016.02.015]

Copy

Modal macro-strain identification from operationalmacro-strain shape under changing loading conditions()

变荷载下基于运行宏应变形状的宏应变模态识别

Share：

Journal of Southeast University (English Edition)[ISSN:1003-7985/CN:32-1325/N]

Volumn:

32

Issue:

2016 2

Page:

219-225

Research Field:

Computer Science and Engineering

Publishing date:

2016-06-20

Info

Title:

Modal macro-strain identification from operationalmacro-strain shape under changing loading conditions

变荷载下基于运行宏应变形状的宏应变模态识别

Author(s):

Li Shu¹, Xu Zhaodong^{1, 2}, Wang Shaojie¹, Wu Zhishen³

¹School of Civil Engineering, Southeast University, Nanjing 210096, China
²Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, Southeast University, Nanjing 210096, China
³International Institute for Urban Systems Engineering, Southeast University, Nanjing 210096, China

李舒¹, 徐赵东^{1, 2}, 王少杰¹, 吴智深³

¹东南大学土木工程学院, 南京210096; ²东南大学混凝土及预应力混凝土结构教育部重点实验室, 南京 210096; ³东南大学城市工程科学国际研究中心, 南京 210096

Keywords:

macro-stain/distributed strain;  fiber Bragg grating(FBG);  operational modal analysis(OMA);  operational deflection shape(ODS);  transmissibility

宏应变/分布式应变;  光纤布拉格光栅;  运行模态分析;  工作变形分析;  传递率

PACS:

TP317

DOI:

10.3969/j.issn.1003-7985.2016.02.015

Abstract:

To develop modal macro-strain(MMS)identification techniques and improve their applicability in a continuous health monitoring system for civil infrastructures, the concept of operational macro-strain shape(OMSS)and the corresponding identification method are proposed under unknown ever-changing loading conditions, and the MMS is then obtained. The core of the proposed technique is mainly based on the specific property that the macro-strain transmissibility tends to be independent of external excitations at the poles of the system and converges to a unique value. The proposed method is verified using the experimental data from a three-span continuous beam excited by an impact hammer at different locations. The identified results are also compared with the commonly used methods, such as the peak-picking(PP)method, the stochastic subspace identification(SSI)method, and numerical results, in the case of unknown input forces. Results show that the proposed technique has unique merits in accuracy and robustness due to its combining multiple tests under changing loading conditions, which also reveal the promising application of the distributed strain sensing system in identifying MMS of operational structures, as well as in the structural health monitoring(SHM)field.

为了发展宏应变模态识别技术并提高其在土木结构健康监测中的适用能力, 提出了运行宏应变形状的概念及相应的获取方法, 并进一步识别了宏应变模态, 以适用结构处于不断变化的未知激励环境.所提新技术的核心是基于宏应变传递率函数在系统极值点独立于激励源并收敛的独特性质.通过对一个三跨连续梁结构模型进行力锤激励, 对所提方法进行了试验验证, 同时将识别结果与未知激励条件下最常用的峰值拾取法(PP)和随机子空间法(SSI)以及数值结果进行了对比分析.结果表明, 该方法联合了多次测试数据, 在不同加载工况下, 其识别结果在精度和稳定性方面具有独特优势, 同时也表明分布式应变传感系统在运行结构宏应变模态识别及结构健康监测领域应用前景好.

References:

[1] Shi Z Y, Law S S, Zhang L M. Improved damage quantification from elemental modal strain energy change [J]. Journal of Mechanical Engineering, 2008, 128(5): 521-529. DOI:10.1061/(asce)0733-9399(2002)128:5(521).(in Chinese)
[2] Yan W J, Huang T L, Ren W X. Damage detection method based on element modal strain energy sensitivity advances in structural engineering [J]. Advances in Structural Engineering, 2010, 13(6): 1075-1088. DOI:10.1260/1369-4332.13.6.1075.
[3] Seyedpoor S M. A two stage method for structural damage detection using a modal strain energy based index and particle swarm optimization [J]. International Journal of Non-Linear Mechanics, 2012, 47(1): 1-8. DOI:10.1016/j.ijnonlinmec.2011.07.011.
[4] Xu Z D, Wu K Y. Damage detection for space truss structures based on strain mode under ambient excitation [J]. Journal of Engineering Mechanics, ASCE, 2012, 138(10): 1215-1223. DOI:10.1061/(asce)em.1943-7889.0000426.
[5] Zong Z H, Ruan Y, Ren W X. Experimental modal analysis of a large-span cable stayed concrete bridge with single tower under ambient excitation [J]. Journal of Vibra-tion Engineering, 2004, 17(5): 684-687.(in Chinese)
[6] Parloo E, Verboven P, Guillaume P, et al. Sensitivity-based operational mode shape normalization [J]. Mechanical Systems and Signal Processing, 2002, 16(5): 757-767. DOI:10.1006/mssp.2002.1498.
[7] Zhang J, Guo S L, Wu Z S, et al. Structural identification and damage detection through long-gauge strain measurements [J]. Engineering Structures, 2015, 99(15): 173-183. DOI:10.1016/j.engstruct.2015.04.024.
[8] Adewuyi A P, Wu Z S, Serker N H M K. Assessment of vibration-based damage identification methods using displacement and distributed strain measurements [J]. Structural Health Monitoring, 2009, 8(6): 443-461. DOI:10.1177/1475921709340964.
[9] Xu Z D, Zeng X, Li S. Damage detection strategy using strain-mode residual trends for long-span bridges [J]. Journal of Computing in Civil Engineering, 2015, 29(5): 04014064-1-04014064-11. DOI:10.1061/(asce)cp.1943-5487.0000371.
[10] Hong W, Wu Z S, Yang C Q, et al. Investigation on the damage identification of bridges using distributed long-gauge dynamic macro-strain response under ambient excitation [J]. Journal of Intelligent Material Systems and Structures, 2012, 23(1): 85-103. DOI:10.1177/1045389x11430743.
[11] Wan C F, Hong W, Wu Z S, et al. Testing and monitoring for a large scale truss bridge using long-gauge fiber optic sensors [J]. Key Engineering Materials, 2013, 569: 223-229. DOI:10.4028/www.scientific.net/kem.569-570.223.
[12] Wan C F, Liu J X, Hong W, et al. Bridge assessment and health monitoring with distributed long-gauge FBG sensors [J]. International Journal of Distributed Sensor Networks, 2013, 2013(6): 494260-1-494260-10. DOI:10.1155/2013/494260.
[13] Yao Z Y, Wang F Q, Liu Y. Stochastic subspace identification method based on continuous model for modal parameters of engineering structures [J]. Journal of Southeast University (Natural Science Edition), 2004, 34(3): 382-385.(in Chinese)
[14] Brincker R, Kirkegaard P H. Special issue on operational modal analysis[J]. Mechanical Systems and Signal Processing, 2010, 24(5):1209-1212. DOI:10.1016/j.ymssp.2010.03.005.
[15] Vold H, Schwarz B, Richardson M H, et al. Measuring operating deflection shapes under non-stationary conditions [C]//Proceedings of SPIE—The International Society for Optical Engineering. San Antonio, USA, 2000: 239-244.
[16] Devriendt C, Guillaume P. Identification of modal parameters from transmissibility measurements [J]. Journal of Sound and Vibration, 2008, 314(1/2):343-356. DOI:10.1016/j.jsv.2007.12.0227.

Memo

Memo:

Biographies: Li Shu(1984—), male, graduate; Xu Zhaodong(corresponding author), male, doctor, professor, zhdxu@163.com.
Foundation items: The National Natural Science Foudation of China(No.51578140), the Natural Science Foundation of Jiangsu Province(No.BK20151092), Scientific Innovation Research of College Graduates in Jiangsu Province(No.CXZZ12_0108).
Citation: Li Shu, Xu Zhaodong, Wang Shaojie, et al. Modal macro-strain identification from operational macro-strain shape under changing loading conditions[J].Journal of Southeast University(English Edition), 2016, 32(2):219-225.doi:10.3969/j.issn.1003-7985.2016.02.015.

Common functions