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Proceedings Paper

Detecting damage in vibrating structures with a scanning LDV
Author(s): A. Z. Khan; Anthony B. Stanbridge; David J. Ewins
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Paper Abstract

It has been demonstrated through experiments on steel and concrete laboratory structures that structural defects or faults, as determined by changes in the dynamic properties or response of structures, can be detected and located using a continuously-scanning Laser Doppler Vibrometer (LDV) if vibration to flex the defects can be induced and if the defects are such as to produce localised mode shape discontinuities. This paper describes such a defect detection method using a short linear LDV scan across the crack location. It has been observed that through cracks are easily detected in thin plates whereas narrow slots in a solid cantilever beam have no easily-identifiable effect on its mode shapes unless cracks extend more than half way through the thickness. Cracks in a reinforced-concrete beam were found to introduce marked and identifiable discontinuities in mode shapes. Keywords: LDV, Vibration, Scanning, Measurement, Cracks, Damage, Structures, Mode Shapes, Modal Analysis, Concrete Beams

Paper Details

Date Published: 1 June 1998
PDF: 9 pages
Proc. SPIE 3411, Third International Conference on Vibration Measurements by Laser Techniques: Advances and Applications, (1 June 1998); doi: 10.1117/12.307730
Show Author Affiliations
A. Z. Khan, Imperial College of Science, Technology and Medicine (United Kingdom)
Anthony B. Stanbridge, Imperial College of Science, Technology and Medicine (United Kingdom)
David J. Ewins, Imperial College of Science, Technology and Medicine (United Kingdom)


Published in SPIE Proceedings Vol. 3411:
Third International Conference on Vibration Measurements by Laser Techniques: Advances and Applications
Enrico Primo Tomasini, Editor(s)

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