Title :
Passive-quadrature demodulated localized-Michelson fiber-optic strain sensor embedded in composite materials
Author :
Valis, Tomas ; Tapanes, Edward ; Liu, Kexing ; Measures, Raymond M.
Author_Institution :
Inst. for Aerosp. Studies, Toronto Univ., Downsview, Ont., Canada
fDate :
4/1/1991 12:00:00 AM
Abstract :
A strain sensor embedded in composite materials that is intrinsic, all fiber, local, and phase demodulated is described. It is the combination of these necessary elements that represents an advance in the state of the art. Sensor localization is achieved by using a pair of mirror-ended optical fibers of different lengths that are mechanically coupled up until the desired gauge length for common-mode suppression has been reached. This fiber-optic sensor has been embedded in both thermoset (Kevlar/epoxy and graphite/epoxy) and thermoplastic (graphite/PEEK) composite materials in order to make local strain measurements at the laminar level. The all-fibre system uses a 3×3 coupler for phase demodulation. Parameters such as strain sensitivity, transverse strain sensitivity, failure strain, and frequency response are discussed, along with applications
Keywords :
demodulation; fibre optic sensors; fibre optics; optical couplers; sensitivity; strain gauges; 3×3 coupler; Kevlar/epoxy; common-mode suppression; composite materials; embedded; failure strain; fibre couplers; frequency response; gauge length; graphite/PEEK; graphite/epoxy; localized-Michelson fiber-optic strain sensor; mirror-ended optical fibers; phase demodulated; phase demodulation; strain sensitivity; thermoplastic; thermoset; Capacitive sensors; Composite materials; Optical coupling; Optical fiber couplers; Optical fiber sensors; Optical fibers; Optical sensors; Sensor phenomena and characterization; Strain measurement; Thermal sensors;
Journal_Title :
Lightwave Technology, Journal of
