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Proceedings Paper

Detection of cracks in aluminum beams using fiber optic polarimetric sensor
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Paper Abstract

On-line monitoring cracks development of the aircrafts in active service is of great significance for flight safety. Fiber optic sensor has its unique advantages over conventional sensors in this aspect. For modern aircrafts, many critical structures are made of aluminum alloys. When structural damage occurs in structures due to cracking, it reduces the stiffness. This charge is reflected in the structure through changes in its dynamic characteristics such as natural frequencies, modal damping. In this paper, the ability of surface mounted fiber optic polarimetric sensor on aluminum vibrating cantilever specimen to detect cracks is studied. Different sources such as He-Ne laser, LD for fiber communication, laser pointer with longer, shorter and very short interference lengths are used in our experiments to evalute their ability for dynamic test, respectively. The preliminary experimental results show that the measured main frequencies will be different for various number of cracks and depths. The three sources, the drift of light intensity and the change of interference contrast will not affect the measured main frequency values. Some of theoretical analysis is also given. From these results, surface mounted fiber optic polarimetric sensors is expected to find its application in monitoring structural integrity of structural members of aircraft in active service.

Paper Details

Date Published: 11 November 1999
PDF: 5 pages
Proc. SPIE 3897, Advanced Photonic Sensors and Applications, (11 November 1999); doi: 10.1117/12.369372
Show Author Affiliations
Jianjun Ma, Nanyang Technological Univ. (Singapore)
Anand Krishna Asundi, Nanyang Technological Univ. (Singapore)

Published in SPIE Proceedings Vol. 3897:
Advanced Photonic Sensors and Applications
Robert A. Lieberman; Anand Krishna Asundi; Hiroshi Asanuma, Editor(s)

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