[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()

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

Author(s):

Li Shu¹;  Xu Zhaodong¹;  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

Keywords:

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

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.

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