Development of fibre optic ingress/egress methods for smart composite structures

Kang, Hyun-Kyu; Jw, Park; Ryu, CY; Hong, Chang Sun; Kim, Chun-Gon

doi:10.1088/0964-1726/9/2/304

Cited by 31 publications

(22 citation statements)

References 10 publications

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“…FBG sensors have high temperature dependence and at high temperatures, there can be distortion of the optical fibers due to the mismatch in the thermal expansion coefficients of the cladding, core and any coating. In mounting or attaching these sensors, the issue of ingress and egress of the optical fiber are major concerns due to the fragile nature of the fibers [9][10][11]. Additionally, the cost of optical interrogators, used for the measurement of FBGs, can be prohibitive for use on small aircraft.…”

Section: Fbg Featuresmentioning

confidence: 99%

Large Scale Applications Using FBG Sensors: Determination of In-Flight Loads and Shape of a Composite Aircraft Wing

Nicolas¹,

Sullivan²,

Richards

2016

Aerospace

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Abstract:Technological advances have enabled the development of a number of optical fiber sensing methods over the last few years. The most prevalent optical technique involves the use of fiber Bragg grating (FBG) sensors. These small, lightweight sensors have many attributes that enable their use for a number of measurement applications. Although much literature is available regarding the use of FBGs for laboratory level testing, few publications in the public domain exist of their use at the operational level. Therefore, this paper gives an overview of the implementation of FBG sensors for large scale structures and applications. For demonstration, a case study is presented in which FBGs were used to determine the deflected wing shape and the out-of-plane loads of a 5.5-m carbon-composite wing of an ultralight aerial vehicle. The in-plane strains from the 780 FBG sensors were used to obtain the out-of-plane loads as well as the wing shape at various load levels. The calculated out-of-plane displacements and loads were within 4.2% of the measured data. This study demonstrates a practical method in which direct measurements are used to obtain critical parameters from the high distribution of FBG sensors. This procedure can be used to obtain information for structural health monitoring applications to quantify healthy vs. unhealthy structures.

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Section: Fbg Featuresmentioning

confidence: 99%

Large Scale Applications Using FBG Sensors: Determination of In-Flight Loads and Shape of a Composite Aircraft Wing

Nicolas¹,

Sullivan²,

Richards

2016

Aerospace

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“…The strategies mainly used are either based on protecting the entry point of the optical fiber during composite fabrication (e.g. using tubing) [3], or based on incorporating a discrete optical connector at the composite edge [4,5]. The first approach does not allow any repair if the fiber breaks at the entry point and often requires an adaptation of the composite production mold to lead out the fiber.…”

Section: Introductionmentioning

confidence: 99%

Low-Loss Connection of Embedded Optical Fiber Sensors Using a Self-Written Waveguide

Missinne

Luyckx²,

Voet³

et al. 2017

IEEE Photon. Technol. Lett.

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Abstract-This letter reports on a new concept for making a low-loss connection to an optical fiber sensor which is embedded in a fiber reinforced composite material for structural health monitoring. First, a cross-section of the composite is made to reveal the end-face of the embedded optical fiber. Then, an external fiber is aligned and an intermediate polymer-based selfwritten waveguide (SWW) is fabricated between both fibers. This SWW bridges the gap and serves as mode size converter ensuring a low-loss optical connection even if both fibers have dissimilar mode field diameters. The advantage of this approach is that no special care needs to be taken during the composite production cycle not to damage the sensor fiber in-or egress points, since it will be reconnected afterwards.

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“…However, surface mounted connectors have also drawbacks: complicated manufacturing (each ply must be split individually and the optical fibre fed through the layers until it finally exits the laminate surface), optical fibre curvature (can induce high optical losses). The third solution is the edge connectors 4,5,6 . This type of fibre-optic connection has advantages such as relatively easy manufacturing and robustness.…”

Section: Introductionmentioning

confidence: 99%

Weakly intrusive optical fibre connector for composite materials applications: vibration and temperature validation tests

et al. 2013

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Due to their high mechanical and corrosion resistance and their small dimension, optical fibre sensors and more particularly fibre Bragg gratings have demonstrated their high utility in the composite material field for monitoring purpose when there are placed under constrain, vibration or temperature variation. In this context the ingress or egress of optical fibre sensors is an important issue for their application in real applications. However, the optical fibre at these transition points is very fragile and an improper handling of the samples can lead to breakage. In this paper, we describe a new kind of "small form factor" optical fibre connectors well suited to be embedded in composite materials. This new connector, cleavable, allows to obtain a good finish of the composite components that can be used in real applications. We also assess its proper behavior (reflection losses evolution) when this embedded connector is tested under vibration and temperature.

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Development of fibre optic ingress/egress methods for smart composite structures

Cited by 31 publications

References 10 publications

Large Scale Applications Using FBG Sensors: Determination of In-Flight Loads and Shape of a Composite Aircraft Wing

Large Scale Applications Using FBG Sensors: Determination of In-Flight Loads and Shape of a Composite Aircraft Wing

Low-Loss Connection of Embedded Optical Fiber Sensors Using a Self-Written Waveguide

Weakly intrusive optical fibre connector for composite materials applications: vibration and temperature validation tests

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