Distributed strain measurement with polymer optical fibers integrated into multifunctional geotextiles

Liehr, Sascha; Lenke, Philipp; Krebber, Katerina; Seeger, Monika; Thiele, E. W.; Metschies, Heike; Gebreselassie, Berhane; Münich, Johannes Christian; Stempniewski, Lothar

doi:10.1117/12.780508

Cited by 50 publications

(42 citation statements)

References 10 publications

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“…The operational principle of FBGs involves monitoring of the wavelength shift in the reflected wavelength spectrum, the extent of which determines the magnitude of strain induced in the FBG. In civil engineering projects, FBGs are commonly used for structural health monitoring (Measures 2001;Connolly 2006;Liehr et al 2008;Guo et al 2011), embankment slope monitoring (Ho et al 2006;Iten 2011;Xu et al 2011), and for measuring the load transfer capacity of piles (SchmidtHattenberger et al 2003;Lee et al 2004a). Recently, the FBG sensors embedded on geosynthetics/geotextiles were also used to detect the soil displacement, strains induced in the pavement, and to monitor the slope stability, etc.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, the FBG sensors embedded on geosynthetics/geotextiles were also used to detect the soil displacement, strains induced in the pavement, and to monitor the slope stability, etc. (e.g., Liehr et al 2008;Dijcker et al 2011;Nöther et al 2012). In railway engineering, the FBG sensors are generally used to monitor the strains induced in rails, and for estimating the weight and speed of trains (Lee et al 2004b;Yoon et al 2011).…”

Section: Introductionmentioning

confidence: 99%

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Application of Optical-Fiber Bragg Grating Sensors in Monitoring the Rail Track Deformations

2015

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The lateral flow of ballast during the passage of trains can reduce the stability of rail tracks. Therefore, it is important to monitor and restrain the movement of ballast accordingly in order to prevent track misalignment. This current study explored the use of optical-Fiber Bragg Grating (FBG) sensors to measure the lateral displacement of unreinforced and geogrid-reinforced ballast. The tests were conducted on fresh latite basalt at a loading frequency of 20 Hz and up to 250 000 load cycles. The test results showed that the FBG sensing system is fully capable of measuring the lateral displacement of ballast under high-frequency cyclic loading. A comparison of strains obtained from FBGs installed at different depths along the ballast depth is made and the lateral strain profiles are measured. Moreover, an empirical model to convert the FBG strains to an equivalent lateral displacement of ballast is proposed to effectively use this technology in realtime monitoring of track deformations. Moreover, an empirical model to convert the FBG strains to an equivalent lateral displacement of ballast is proposed to effectively use this technology in real-time monitoring of track deformations.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Application of Optical-Fiber Bragg Grating Sensors in Monitoring the Rail Track Deformations

2015

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“…A similar effect has been discussed in liquid-core optical fibers [37] but is not measurable in silica fibers. We previously showed that the Rayleigh backscatter intensity in PMMA POF changes relatively linear with temperature (about 0.005 dB/K) [4]. This effect can be used to measure temperature differences between adjacent fiber sections.…”

Section: B Sensor Applicationmentioning

confidence: 96%

Femtosecond Laser Structuring of Polymer Optical Fibers for Backscatter Sensing

Liehr

Burgmeier

Krebber

et al. 2013

J. Lightwave Technol.

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Focused femtosecond laser pulses are used to create scattering damage in the core of polymer optical fibers (POF). The resulting structures are investigated regarding morphology by light microscopy and backscattered intensity using optical time domain reflectometry (OTDR). Quasi-distributed optical fiber sensing is proposed by evaluating backscatter changes at the inscribed scatter centers. Application examples for quasi-distributed measurement of fiber bends and temperature are demonstrated. Index Terms-Femtosecond laser, micromachining, optical fiber sensors, polymer optical fiber, polymer.

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“…In the recent past, the FBG sensing system was successfully used in the structural health monitoring (Liehr et al 2008;Guo et al 2011) and in monitoring the slope stability (Dijcker et al 2011;Nöther et al 2012). In railway engineering, it was used to monitor the strains induced in rails, and for estimating the weight and speed of trains (Lee et al 2004;Yoon et al 2011).…”

Section: Instrumentation To Capture Internal Lateral Strains In Ballamentioning

confidence: 99%

A laboratory investigation to assess the functioning of railway ballast with and without geogrids

Hussaini

Indraratna

Vinod

2016

Transportation Geotechnics

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Understanding the complex load transfer mechanism and the subsequent accumulation of deformation in ballast and subballast layers under repeated wheel loading is essential to design resilient rail tracks. Large-scale cyclic tests have been conducted on railroad ballast instrumented with optical based fibre Bragg grating (FBG) sensors, LVDTs, pressure plates and the settlement pegs to explore the role of geogrid and its interaction with ballast in improving the track performance. Latite basalt and geogrids with different aperture sizes were used for the investigations. The laboratory experimental results indicate that the geogrid inclusions enhance track performance by arresting the lateral spreading of ballast and thereby significantly reducing the extent of its vertical settlement. In contrast, the reinforcement of ballast with geogrid has only a marginal effect on reducing the settlement in the subballast layer. The results also show that geogrid minimises the amount of particle breakage, the effectiveness of which is governed by its placement position, with lowest breakage occurring when the geogrid is placed at a location 130 mm above the subballast. In addition, geogrids also reduce the extent of vertical stress in the subgrade soil. The laboratory test results establish beyond doubt the effectiveness of FBG sensing system in capturing the ballast movement under cyclic loading. Disciplines Engineering | Science and Technology Studies

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Distributed strain measurement with polymer optical fibers integrated into multifunctional geotextiles

Cited by 50 publications

References 10 publications

Application of Optical-Fiber Bragg Grating Sensors in Monitoring the Rail Track Deformations

Application of Optical-Fiber Bragg Grating Sensors in Monitoring the Rail Track Deformations

Femtosecond Laser Structuring of Polymer Optical Fibers for Backscatter Sensing

A laboratory investigation to assess the functioning of railway ballast with and without geogrids

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