Crack detection in a simply supported RC beam using simplified Laplacian

Razak, H.A. and Teng, S.L. and Ismail, Z. and Abdul Rahman, A.G. (2001) Crack detection in a simply supported RC beam using simplified Laplacian. Proceedings of the International Modal Analysis Conference - IMAC, 2. pp. 1344-1350. ISSN 10466770 ,

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This paper describes the detection and identification of cracking severity in a reinforced concrete beam using modal data. Experimental modal test was performed on the beam before and after application of load of increasing intensity to induce a single crack at a fixed location. Modal parameters extracted were categorised into two groups, namely local response parameter (mode shape data) and global response parameters. Localised changes such as cracking reduce the stiffness of the structure, and therefore caused a localised change in the discrete function of the mode shape. From a previous research, Laplacian Operator was initially proposed. However, when applied to a non-homogeneous and composite material such as reinforced concrete, the operator was too sensitive and did not yield meaningful results. Hence, a simplified Laplacian operator was suggested. In this investigation, it was found that global response such as natural frequency is a good indicator to detect the occurrence of the deterioration in the structure. However, the local response data such as mode shape was required to detect the defect location accurately and a simplified Laplacian operator worked quite successfully. Furthermore, it was observed that the higher frequency modes tend to detect the occurrence of cracking in the earlier stages.

Item Type: Article
Additional Information: Conference code: 58059 Export Date: 16 December 2013 Source: Scopus CODEN: PMCNE Language of Original Document: English Correspondence Address: Razak, H.A.; Department of Civil Engineering, Faculty of Engineering, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur, Malaysia References: Ratcliffe, C.P., Damage detection using a modified laplacian operator on mode shape data (1997) Journal of Sound and Vibration, 204 (3), pp. 505-517. , January; Chondros, T.G., Dimarogonas, A.D., Identification of Crack in Welded Joints of Complex Structure (1980) Journal of Sound and Vibration, 69, pp. 531-538; Masoud, S., Jarrad, M.A., Al-Maamory, M., Effect of crack depth on the natural frequency of a prestressed fixed-fixed beam (1998) Journal of Sound and Vibration, 214 (2), pp. 201-212; Ismail, F., Ibrahim, A., Martin, H.R., Identification of fatigue cracks from vibration testing (1989) Journal of Sound and Vibration, 138, pp. 305-317. , October; Ostachowicz, W.M., Krawczuk, M., Analysis of the effect of crack on the natural frequencies of a cantilever beam (1990) Journal of Sound and Vibration, 150 (2), pp. 191-201. , October; Pandey, A.K., Biswas, M., Samman, M.M., Damage detection from changes in curvature mode shape (1990) Journal of Sound and Vibration, 145 (2), pp. 321-332. , May
Uncontrolled Keywords: Cracks, Laplace transforms, Mathematical operators, Modal analysis, Natural frequencies, Parameter estimation, Reinforced concrete, Stiffness, Crack detection, Laplacian operator, Reinforced concrete beam, Concrete beams and girders
Subjects: T Technology > TA Engineering (General). Civil engineering (General)
Divisions: Faculty of Engineering
Depositing User: Mr Jenal S
Date Deposited: 24 Jan 2014 14:27
Last Modified: 20 Oct 2014 06:25

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