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Journal ArticleDOI

Cure monitoring of smart composites using Fiber Bragg Grating based embedded sensors

01 Feb 2000-Sensors and Actuators A-physical (Elsevier)-Vol. 79, Iss: 2, pp 153-161
Abstract: A sensor embedded in the composite laminate can act as a temperature transducer during the composite cure mechanism. Once the composite is cured, the same sensor can be used to provide the information about the mechanical changes that influence the performance of the material. Fiber Bragg Grating (FBG) sensor is one such sensor which one can use for the composite cure monitoring. We present here the results obtained with an associated FBG sensor system for the cure monitoring of smart composites. The performance of the embedded FBG sensor smart composite specimens under 3- and 4-point bending conditions are also being investigated. Finally, the performance analysis has been extended to cantilever specimens.
Citations
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Journal ArticleDOI
TL;DR: This paper provides a tutorial introduction, a comprehensive background on this subject and also a forecast of the future of OFS for SHM, including those from the renewable energy, transportation, civil engineering and the oil and gas industry sectors.
Abstract: Structural Health Monitoring (SHM) can be understood as the integration of sensing and intelligence to enable the structure loading and damage-provoking conditions to be recorded, analyzed, localized, and predicted in such a way that nondestructive testing becomes an integral part of them. In addition, SHM systems can include actuation devices to take proper reaction or correction actions. SHM sensing requirements are very well suited for the application of optical fiber sensors (OFS), in particular, to provide integrated, quasi-distributed or fully distributed technologies. In this tutorial, after a brief introduction of the basic SHM concepts, the main fiber optic techniques available for this application are reviewed, emphasizing the four most successful ones. Then, several examples of the use of OFS in real structures are also addressed, including those from the renewable energy, transportation, civil engineering and the oil and gas industry sectors. Finally, the most relevant current technical challenges and the key sector markets are identified. This paper provides a tutorial introduction, a comprehensive background on this subject and also a forecast of the future of OFS for SHM. In addition, some of the challenges to be faced in the near future are addressed.

609 citations


Cites background or methods from "Cure monitoring of smart composites..."

  • ...Although blade condition monitoring is the most typical application of optical fiber sensors, these can be placed in almost the whole wind turbine starting from the fabrication stage, in which temperature and strain can be monitored in the curing processes using FBGs [68] or Brillouin technology [74] to assess the mechanical properties of the carbon fiber reinforced plastic (CFRP) pieces....

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  • ...Other works have explored the use of FBG sensors to monitor the distribution of strain and temperature [68], showing its feasibility to detect the onset of vitrification and to measure the residual strain after curing....

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Journal ArticleDOI
23 Apr 2014-Sensors
TL;DR: The main challenges arising from the use of FBGs in composite materials are reviewed, with a focus on issues related to temperature-strain discrimination, demodulation of the amplitude spectrum during and after the curing process as well as connection between the embedded optical fibers and the surroundings.
Abstract: Nowadays, smart composite materials embed miniaturized sensors for structural health monitoring (SHM) in order to mitigate the risk of failure due to an overload or to unwanted inhomogeneity resulting from the fabrication process. Optical fiber sensors, and more particularly fiber Bragg grating (FBG) sensors, outperform traditional sensor technologies, as they are lightweight, small in size and offer convenient multiplexing capabilities with remote operation. They have thus been extensively associated to composite materials to study their behavior for further SHM purposes. This paper reviews the main challenges arising from the use of FBGs in composite materials. The focus will be made on issues related to temperature-strain discrimination, demodulation of the amplitude spectrum during and after the curing process as well as connection between the embedded optical fibers and the surroundings. The main strategies developed in each of these three topics will be summarized and compared, demonstrating the large progress that has been made in this field in the past few years.

380 citations


Cites methods from "Cure monitoring of smart composites..."

  • ...They have been used to follow the curing cycle [76,77], the resin polymerization process [78,79] and the formation of residual strain [80]....

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Journal ArticleDOI
TL;DR: In this paper, the extrinsic Fabry-Perot interferometer (EFPI) and fiber Bragg grating (FBG) sensors are real-time employed to simultaneously monitor the cure process of CFRP composite laminates with and without damage.
Abstract: Structural health monitoring (SHM) including the real-time cure monitoring and non-destructive evaluation (NDE) in-service is very important and definitely demanded for safely working of high performance composite structures in situ. It is very difficult to carry out by using conventional methods. A unique opportunity was provided to real-time monitor the health status of composite structures by using embedded fiber optic sensors (FOSs). In this paper, the extrinsic Fabry–Perot interferometer (EFPI) and fiber Bragg grating (FBG) sensors are real-time employed to simultaneously monitoring the cure process of CFRP composite laminates with and without damage. The results show that both embedded EFPI and FBG sensors could be used to monitor the cure progress of composite materials and detect the occurred damage on-line during the fabrication of composite structures. Furthermore, the NDE of smart composite laminates embedded both EFPI and FBG sensors are performed by using the three-point bending test. The experimental results present that the flexural strain of CFRP composite laminates with damage is more than that of CFRP laminates without damage under same load as we expected. Both EFPI and FBG sensors also show the excellent correlation during the cure monitoring and bending test.

251 citations

Journal ArticleDOI
TL;DR: In this article, a multi-disciplinary research program on fiber bragg grating sensors involving the School of Civil and Structural Engineering at Nanyang Technological University in Singapore is reported.

250 citations

Journal ArticleDOI
TL;DR: In this paper, extrinsic Fabry-Perot interferometer (EFPI) and fiber Bragg grating (FBG) sensors are embedded in carbon/epoxy composite laminates and used to monitor the cure process simultaneously.
Abstract: Real-time cure monitoring of composite materials is very important to improve the performance of advanced composite materials. It is very difficult to monitor the cure process online using conventional methods. Fiber optic sensors in smart composite materials provide a unique opportunity to monitor the cure process of composite materials in real time by using embedded sensors. In this paper, extrinsic Fabry-Perot interferometer (EFPI) and fiber Bragg grating (FBG) sensors are embedded in carbon/epoxy composite laminates and used to monitor the cure process simultaneously. Furthermore, measurements of residual strains of composite laminates during the cure have been performed. The results show that both EFPI and FBG sensors can be used to monitor the strain development of composite laminates with and without damage during cure. An excellent correlation between the EFPI and FBG sensors is presented.

133 citations

References
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BookDOI
11 Jul 2011
TL;DR: Udd et al. as discussed by the authors described the emergence of fiber-optic sensor technology and its application in industrial applications, including light sources, sensors, and sensors based on the Sagnac Interferometer and passive ring resonance.
Abstract: Preface. About the Authors. Contributors. 1 The Emergence of Fiber Optic Sensor Technology (Eric Udd). 2 Optical Fibers (Daniel A. Nolan, Paul E. Blaszyk, and Eric Udd). 3 Light Sources (Eric Udd). 4 Optical Detectors (William B. Spillman, Jr.). 5 Optical Modulators for Fiber Optic Sensors (Leonard M. Johnson). 6 Intensity-Based and Fabry Perot Interferometer Sensors (Gordon L. Mitchell). 7 Multimode Grating Sensors (William B. Spillman, Jr.). 8 Multimode Polarization Sensors (William B. Spillman, Jr.). 9 Fiber Optic Sensors Based on the Sagnac Interferometer and Passive Ring Resonator (Eric Udd). 10 Fiber Optic Sensors Based on the Mach Zehnder and Michelson Interferometers (Anthony Dandridge). 11 Distributed and Multiplexed Fiber Optic Sensors (Alan D. Kersey). 12 Fiber Optic Magnetic Sensors (Frank Bucholtz). 13 Industrial Applications of Fiber Optic Sensors (John W. Berthold III). 14 Fiber Optic Smart Structures (Eric Udd). 15 Fiber Grating Sensors (Eric Udd). 16 Fiber Optic Biosensors (William B. Spillman, Jr.). Index.

777 citations

BookDOI
01 Jan 1999
TL;DR: In this article, the authors present an overview of the development of optical fiber sensor technology and its application in the field of temperature measurement and current measurement, as well as other applications.
Abstract: List of contributors. Preface. 1. Overview of fiber sensor developments D.A. Jackson. 2. Foundations of optical fiber technology V. Handerek. 3. Sources for optical fiber sensors K.T.V. Grattan. 4. Optical detectors and receivers J.D.C. Jones. 5. Multimode optical fiber sensors G.R. Jones, R.E. Jones, R. Jones. 6. Multimode optical fiber chemical sensors J.O.W. Norris. 7. Single mode optical fiber sensors V. Handerek. 8. Optical fiber modulation techniques for single mode fiber sensors R.P. Tatam. 9. Fiber optic white-light interferometric sensors B.T. Meggitt. 10. Nonlinear effects in optical fibers A.J. Rogers. 11. Distributed fiber optic sensors A.H. Hartog. 12. Schemes for referencing of intensity-modulated optical sensor systems G. Murtaza, J.M. Senior. 13A. Hybrid optical fiber sensors R.C. Spooncer, G.S. Philp. 13B. Optical fiber current measurement A.J. Rogers. 13C. Fiber optic techniques for temperature measurement K.T.V. Grattan. 14. Advanced external fiber optic sensors D.A. Jackson. Index.

284 citations

Proceedings ArticleDOI
01 Dec 1990
TL;DR: In this paper, Bragg gratings have been exposed into the core of optical fibers at specific locations to implement distributed, discrete gages for measurement of strain and temperature for composite specimen curing and bending.
Abstract: Bragg gratings have been exposed into the core of optical fibers at specific locations to implement distributed, discrete gages for measurement of strain and temperature. Demonstrations using these devices to monitor composite specimen curing and bending are discussed. The sensor signals are also used in a control loop to drive an actuator for active damping of the test sample.

70 citations

Book ChapterDOI
01 Jan 1993

16 citations

Proceedings ArticleDOI
06 Jun 1997
TL;DR: In this paper, a comparative study was conducted for different types of optical fiber sensor developed to monitor the cure of an epoxy resin system. And the advantages and disadvantages of these three methods are discussed.
Abstract: This paper reports on a comparative study undertaken for different types of optical fiber sensor developed to monitor the cure of an epoxy resin system. The optical fiber sensors used to monitor the cure process were based on transmission spectroscopy, evanescent wave spectroscopy and refractive index monitoring. The transmission sensor was prepared by aligning two optical fibers within a specially prepared sleeve with a gap between the optical fiber end-faces. During cure, resin from the specimen flowed into the gap between the optical fibers allowing transmission spectra of the resin to be obtained. The evanescent wave sensor was prepared by stripping the cladding from a high refractive index core optical fiber. The prepared sensor was embedded in the sample and attenuated total reflectance spectra recorded from the resin/core boundary. Refractive index monitoring was undertaken using a high refractive index core optical fiber which had a small portion of its cladding removed. The prepared sensor was embedded in the resin specimen and light from a single wavelength source was launched into the fiber. Changes in the guiding characteristics of the sensor due to refractive index changes at the resin/core boundary were used to monitor the progress of the cure reaction. The transmission and evanescent wave spectroscopy sensors were used to follow changes in characteristic near-infrared absorption bands of the resin over the range 1450 - 1700 nm during the cure reaction. Consequently these techniques required tunable wavelength sources covering specific wavelength ranges. However, the refractive index based sensor used a single wavelength source. Therefore the equipment costs for this type of sensor were considerably less. Additionally, the refractive index sensor did not require a single wavelength source at any particular wavelength and could be applied to any spectral region in which the optical fiber would transmit light. The advantages and disadvantages of these three methods are discussed.

15 citations