Evaluation of Rugged 'Smart Patch' Fibre-Optic Strain Sensors

Article Preview

Abstract:

Fibre-optic sensors have advantages over existing electrical sensors in many strain and stress monitoring applications. However, bare optical fibres are fragile and packaging techniques must be developed before these sensors can be used more widely. One such method is the Smart Patch, in which the fibre Bragg grating is encapsulated between plies of glass-reinforced epoxy where rugged cables are anchored. This forms a flat flexible patch in which the fibre is protected from mechanical and environmental damage. However, it is important that the mechanical strength of the patch is not achieved at the expense of good strain transfer characteristics. To confirm this, fibre Bragg gratings with acrylate and polyimide coatings were embedded in a glass-epoxy patch that was bonded to an aluminium tensile specimen. An electrical strain gauge was also bonded to the specimen to provide a strain reference. Tests were carried out at different loading rates and at temperatures from -30°C to +80°C. There was good agreement between the fibre-optic sensors and the electrical strain gauge demonstrating that the patch performed in a practically identical manner to the conventional gauges. A second experiment on a representative part of ship structure demonstrated the versatility of the patch.

You might also be interested in these eBooks

Info:

Periodical:

Pages:

343-348

Citation:

Online since:

August 2006

Export:

Price:

Permissions CCC:

Permissions PLS:

Сopyright:

© 2005 Trans Tech Publications Ltd. All Rights Reserved

Share:

Citation:

[1] A. Othonos and K. Kalli, Fiber Bragg Gratings: Fundamentals and Applications in Telecommunications and Sensing, Pub. Artech Ho. (1999).

Google Scholar

[2] H. Davies, L. Everall, A. Gallon, Structural health monitoring using smart optical fibre sensors, Proc. Smart Materials, Eds. A. Wilson and H. Asanuma, Melbourne, Dec 10-12 (2000).

DOI: 10.1117/12.424399

Google Scholar

[3] J.M. Dulieu-Smith, R.A. Shenoi, P.J.C.L. Read, S. Quinn and S.S.J. Moy, Thermoelastic stress analysis of a GRP tee joint, J. App. Composite Matls., 1997, 4, pp.283-303.

DOI: 10.1007/bf02481395

Google Scholar

[4] MIL-HDBK5H, Metallic materials and elements for aerospace vehicle structures, Pub. U.S. DoD, pp.3-265, (1998).

Google Scholar