Damage detection for beam structures based on local flexibility method and macro-strain measurement

다국어 초록 (Multilingual Abstract)

Many vibration-based global damage detection methods attempt to extract modal parameters from vibration signals as the main structural features to detect damage. The local flexibility method is one promising method that requires only the first few fundamental modes to detect not only the location but also the extent of damage. Generally, the mode shapes in the lateral degree of freedom are extracted from lateral vibration signals and then used to detect damage for a beam structure. In this study, a new approach which employs the mode shapes in the rotary degree of freedom obtained from the macro-strain vibration signals to detect damage of a beam structure is proposed. In order to facilitate the application of mode shapes in the rotary degree of freedom for beam structures, the local flexibility method is modified and utilized. The proposed rotary approach is verified by numerical and experimental studies of simply supported beams. The results illustrate potential feasibility of the proposed new idea. Compared to the method that uses lateral measurements, the proposed rotary approach seems more robust to noise in the numerical cases considered. The sensor configuration could also be more flexible and customized for a beam structure. Primarily, the proposed approach seems more sensitive to damage when the damage is close to the supports of simply supported beams.

참고문헌 (Reference)

• 1 Yung, B. L., "The health monitoring of a prestressed concrete beam by using fiber Bragg grating sensors" 13 (13): 712-718, 2004
• 2 Van Overschee, P., "Subspace Identification for Linear Systems: Theory - Implementation -Applications" Kluwer Academic Publishers 1996
• 3 Ming L. Wang, "Sensor enriched infrastructure system" 국제구조공학회 6 (6): 309-333, 2010
• 4 Johnson, E., "Phase I IASC-ASCE structural health monitoring benchmark problem using simulated data" 130 (130): 3-15, 2004
• 5 Li, S. Z., "Parametric estimation for RC flexural members based on distributed long-gauge fiber optic sensors" 136 (136): 144-151, 2010
• 6 Cardini, A. J., "Long-term structural health monitoring of a multigirder steel composite bridge using strain data" 8 (8): 47-58, 2009
• 7 Fan, N. Y., "Localized long gage fiber optic strain sensors" 7 (7): 257-, 1998
• 8 Bernal, D., "Load vectors for damage localization" 128 (128): 7-14, 2002
• 9 Ni, Y., "In-service condition assessment of bridge deck using long-term monitoring data of strain response" 17 (17): 876-885, 2012
• 10 Ansari, F., "Fiber optic health monitoring of civil structures using long gage and acoustic sensors" 14 (14): S1-, 2005
• 11 Licheng Wang, "Fatigue performance monitoring of full-scale PPC beams by using the FBG sensors" 국제구조공학회 13 (13): 943-957, 2014
• 12 Matthys, S., "Experimental testing of posttensioned concrete girders instrumented with optical fiber gratings" 1060-1063, 2005
• 13 Li, S. Z., "Development of distributed long gage fiber optic sensing system for structural health monitoring" 6 (6): 133-143, 2007
• 14 Wan, L. B., "Determination of internal strain of concrete beam using fiber Bragg grating sensors" 13 (13): 722-725, 2002
• 15 Toksoy, T., "Bridge-condition assessment by modal flexibility" 34 (34): 271-278, 1994
• 16 Abdo, M. A. B., "A numerical study of structural damage detection using changes in the rotation of mode shapes" 251 (251): 227-239, 2002
• 17 Reynders, E., "A local flexibility method for vibration-based damage localization and quantification" 329 (329): 2367-2383, 2010