Structural Monitoring Using Fiber-Optic Bragg Grating Sensors

Betz, Daniel; Staudigel, L.; Trutzel, Michael N.; Kehlenbach, Michael

doi:10.1177/1475921703002002006

Cited by 37 publications

(14 citation statements)

References 9 publications

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“…[1][2][3][4][5] Thus far, the FBG sensors' capability to measure physical quantities such as the temperature, strain, pressure, etc., has been studied extensively. [2][3][4][5][6][7][8] However, the use of FBG sensors for detection of environmental refractive index change has not been fully explored. Refractive index sensing is important for biological and chemical applications since a number of substances can be detected through measurements of the refractive index.…”

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confidence: 99%

Highly sensitive fiber Bragg grating refractive index sensors

Liang

Huang

et al. 2005

Applied Physics Letters

585

254

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We combine fiber Bragg grating ͑FBG͒ technology with a wet chemical etch-erosion procedure and demonstrate two types of refractive index sensors using single-mode optical fibers. The first index sensor device is an etch-eroded single FBG with a radius of 3 m, which is used to measure the indices of four different liquids. The second index sensor device is an etch-eroded fiber Fabry-Pérot interferometer ͑FFPI͒ with a radius of ϳ1.5 m and is used to measure the refractive indices of isopropyl alcohol solutions of different concentrations. Due to its narrower resonance spectral feature, the FFPI sensor has a higher sensitivity than the FBG sensor and can detect an index variation of 1.4ϫ 10 −5 . Since we can measure the reflection signal, these two types of sensors can be fabricated at the end of a fiber and used as point sensors. Since the early 1990s, fiber Bragg grating ͑FBG͒ sensors have been intensively developed due to their many desirable advantages such as the small size, absolute measurement capability, immunity to electromagnetic interference, wavelength multiplexing, and distributed sensing possibilities. [1][2][3][4][5] Thus far, the FBG sensors' capability to measure physical quantities such as the temperature, strain, pressure, etc., has been studied extensively. [2][3][4][5][6][7][8] However, the use of FBG sensors for detection of environmental refractive index change has not been fully explored. Refractive index sensing is important for biological and chemical applications since a number of substances can be detected through measurements of the refractive index. [2][3][4][8][9][10][11][12][13] For normal FBGs, removal of the fiber cladding is required to increase the evanescent field interaction with the surrounding environment. This concept has been demonstrated using D-shaped fiber and sidepolished fiber. 9,11,12 In both cases, the strength and durability of the sensor were greatly reduced. Special fiber was also needed, which would raise the costs and limit the possible applications. Long-period fiber gratings have also been demonstrated to have high sensitivity to the refractive index of the ambient media, 2,3,13-15 however, their multiple resonance peaks and broad ͑typically tens of nanometers͒ transmission resonance features limit the measurement accuracy and their multiplexing capabilities. 9 In addition, the relatively long length of the grating limits their application as point sensor devices.In this letter, we first demonstrate a single etch-eroded FBG sensor using standard single-mode telecommunication fiber ͑Corning SMF-28͒. Fiber Fabry-Pérot interferometers ͑FFPIs͒ have also been widely used as sensors. 2,3,16,17 Compared to a single FBG, the FFPI sensors possess narrower resonance peaks and are more desirable for high accuracy wavelength measurement. 2,3,9,18 To that end we propose and demonstrate an etch-eroded FFPI sensor formed by two FBGs. The FFPI sensor is used to measure the refractive index of isopropyl alcohol ͑IPA͒ solutions of different concentrations, exhibiting the capabi...

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confidence: 99%

Highly sensitive fiber Bragg grating refractive index sensors

Liang

Huang

et al. 2005

Applied Physics Letters

585

254

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“…The paint that passes through the holes fixes the fiber onto the surface. Then, when the paint is dried, the tape is removed and more layers of paint are sprayed [17].…”

Section: Methods Of Attaching the Sensors To The Structurementioning

confidence: 99%

“…However, optical sensors have high temperature sensitivity which might be a limitation for certain applications [17].…”

Section: Advantages and Disadvantages Of Fiber-optic Sensorsmentioning

confidence: 99%

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Determination of the strain distribution in adhesive joints using Fiber Bragg Grating (FBG)

Silva

Moreira

Loureiro

2012

Journal of Adhesion Science and Technology

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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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Structural Monitoring Using Fiber-Optic Bragg Grating Sensors

Cited by 37 publications

References 9 publications

Highly sensitive fiber Bragg grating refractive index sensors

Highly sensitive fiber Bragg grating refractive index sensors

Determination of the strain distribution in adhesive joints using Fiber Bragg Grating (FBG)

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

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