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Proceedings Paper

A comparison of interrogation schemes for impact event monitoring using fiber Bragg gratings
Author(s): C. S. Shin; B. L. Chen
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Paper Abstract

Fiber Bragg gratings (FBGs) are capable of acquiring transient impact signals and are suitable for impact event monitoring and impact position locating. Previous application of this technique showed that the accuracy and the range within which the impact position can be located is limited. A detailed analysis concluded that the major cause of the above limitations was due to poor equipment resolution and angular insensitivity of the FBG. In order to minimize the number of FBGs deployed yet still maintains reasonable prediction accuracy and locating range, the sensitivity of the interrogation system has to be optimized. To identify a better technique to serve the above purpose, four different interrogating schemes have been compared in the current work. The configurations with an ASE light source modified by a commercial edge filter or an FBG are the least sensitive but remained stable under all impact conditions. In the other two configurations which comprise a ring laser scheme, the one with the sensing FBG being part of the laser ring is extremely sensitive and is capable of detecting the impact of a 70g projectile from a height of 0.1mm at a distance of 60cm. However, with increasing impact severity, the system may become unstable. The configuration where the sensing FBG is not part of the laser ring gives a good compromise between sensitivity and stability. Based on the above results, the implications on the sensitivities and limitations of the different configurations when used for impact event monitoring on large structures will be discussed.

Paper Details

Date Published: 21 October 2009
PDF: 6 pages
Proc. SPIE 7493, Second International Conference on Smart Materials and Nanotechnology in Engineering, 749314 (21 October 2009); doi: 10.1117/12.840382
Show Author Affiliations
C. S. Shin, National Taiwan Univ. (Taiwan)
B. L. Chen, National Taiwan Univ. (Taiwan)


Published in SPIE Proceedings Vol. 7493:
Second International Conference on Smart Materials and Nanotechnology in Engineering
Jinsong Leng; Anand K. Asundi; Wolfgang Ecke, Editor(s)

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