Post on 06-May-2020
Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring
Pavol StajancaDivision 8.6 Fibre Optic Sensors
10.04.2019
1
Federal Institute for Material Research and Testing (BAM)
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring2
• National research, testing and advisory body for safety in technology and chemistry
• BAM• Dep. 8: Non-destructive testing
• Div. 8.6: Fiberoptic sensors
Various competences in fiberoptic sensing (FOS):
• Point sensors (FBGs, Interferometers)• Distributed FOS (Rayleigh, Brillouin, Raman)• Polymer optical fiber sensors• Development of novel FOS techniques• Application/integration of fibers in structures
Fiberoptic sensors (FOS)
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring3
• Compact• Lightweight• Electrically passive• Immune to electromagnetic interference• High temperature/pressure/chemical/radiation resistance• Possibility of real-time remote sensing• Multi-point & distributed sensing possible (long distances)
Point sensor
Fully-distributed sensor
Multi-point (multiplexed) sensorT
z
Measurands:• Strain• Temperature• Pressure• Humidity• Chemicals• Radiation
Distributed FOS
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring4
Light backscattering in optical fiber• Rayleigh - Material inhomogeneities • Raman - Thermal molecular vibrations
(optical phonons)• Brillouin - Coherent material lattice
vibrations (acoustic phonons)
Spatially-continuous distributed measurement over extended distances• Strain and temperature are the most common measurands
Position
Bac
ksca
tter
in
ten
sity
PositionBac
ksca
tter
in
tens
ity
Brillouin
Wavelength
Bac
ksca
tter
inte
nsi
ty
Raman
StokesAnti-Stokes
Rayleigh
Incident light
FOS markets
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring5
• Strain and temperature monitoring of large civil, energy and geotechnical structures
https://omnisens.com
https://fibercore.com
https://cleanenergywire.org http:/powerspecialties.com
FOS in nuclear waste management
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring6
• Structural health monitoring (SHM)• Temperature monitoring
Delepine-Lesoille et al., J. Sensors 2012 (2012), 369375.
SHM of underground nuclear waste repository (ANDRA, France)
FBG temperature monitoring in nuclear waste containers (ONDRAF, Belgium)
Kinet et al., IEEE Trans. Nucl. Sci. 63 (2016), 1955.
Alternative FOS applications
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring7
Polymer optical fibers for large-strain sensing
Polymer optical fibers for radiation monitoring
Distributed vibration/acoustic
sensing
eeensingngnnnnnnngggg:::: frfrfrfromom llllllarargegeggg - ttttttststraraininii aaaappppppppllililililiilicacacacatiitititititiononononss sss ttototototo aaaacocousuuususuussuuuususuu titittttttt c em sssision mooooooononnoonononooooononiitititititititittititororrororororiiiiinininnininingggggg1010.04.4.220202022202020202002022022222222220222 1919199 NiNiNichcheses oof fibeberoroptptt77
Polymer vs. glass optical fibers
Polymer optical fibers (POFs)• Higher elasticity and lower stiffness• High ultimate strain limit (up to 100%)• Easy handling (user friendlier)• Ease of processing• Cheap
Drawback -> higher attenuation
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring8
Brittle material (glass)
Ductile material (polymer)
Rayleigh-based strain sensing with POFs
Local backscatter increase• Large-core PMMA POF• Optical time-domain
reflectometry (OTDR)
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring9
Position
Bac
ksca
tter
Int
ensi
tyPOF strainOTDR
Fiber length-change measurement• Perfluorinated Cytop POF• Incoherent optical frequency-
domain reflectometry (I-OFDR)
Liehr et al., IEEE Sensors 9 (2009), 1330-1338.
e Fi
Large-strain sensingPMMA POF
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring10
Krebber, Current Developments in Optical Fiber Technology (IntechOpen, 2013), 319-344.
• Large 1 mm step-index PMMA POF• Commercial OTDR interrogator
• Limited monitoring range (<100m) and resolution (>0.5m)
Tear-off edge detection
( )
Crack detection
Large-strain sensingCytop POF
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring11
Liehr et al., Meas. Sci. Technol 21 (2010), 094023.
• Low-loss graded-index Cytop POF• Self-developed I-OFDR interrogator
• Improved performance• Extended monitoring range up to 500 m• Strain limit in excess of 100%• Spatial resolution down to single millimetres
Alternative FOS applications
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring12
Polymer optical fibers for large-strain sensing
Polymer optical fibers for radiation monitoring
Distributed vibration/acoustic
sensing
eeensingngnnnnnnngggg:::: frfrfrfromom llllllarargegeggg - ttttttststraraininii aaaappppppppllililililiilicacacacatiitititititiononononss sss ttototototo aaaacocousuuususuussuuuususuu titittttttt c em1010.04.4.220202022202020202002022022222222220222 1919199 NiNiNichcheses oof fibeberoroptptt11212 sssision mooooooononnoonononooooononiitititititititittititororrororororiiiiinininnininingggggg
Radiation-induced attenuation (RIA)
Radiation-induced material defects (color centers)• Strongly material & wavelength dependent• Typically viewed as negative effect
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring13
Detector
, = 10 log )( , )( , 0Light
source
Wavelength
Fibe
r tr
ansm
issi
onFi
ber
tran
smis
sion
Wavelengthgg
Fiber
0 Gy
5 Gy
10 Gy
15 Gy
20 Gy
Stajanca & Krebber, POF 2017 Conference (2017, Aveiro, Portugal), p. 5.C f (20 l)
@ 460 nm
• RIA magnitude related to total absorbed dose
@ 460 n
Cytop POF RIA
Sensitivity140 dBm-1/kGy (@ 460 nm)50 dBm-1/kGy (@ 650 nm)
Fiberoptic distributed radiation measurement
Distributed measurement of fiber attenuation profile
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring14
Position
Bac
ksca
tter
in
tens
ity
processing
Position
Dos
e [G
y]
attenua
Distributed dose detection with POF
Distributed RIA measurement• Cytop POF + 650 nm OTDR• Gamma irradiation (20 Gy) with 60Co source
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring15
Stajanca et al., Sensors 17 (2017), 1959.Stajanca et al., Sensors 17 (2017), 1959.
Cytop POF
Fiberoptic distributed radiation monitoring for NWD applications
High-resolution & high-sensitivity distributed dose measurement• Radiation leak detection• Short-term NW container integrity control
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring16
Alternative FOS applications
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring17
Polymer optical fibers for large-strain sensing
Polymer optical fibers for radiation monitoring
Distributed vibration/acoustic
sensing
eeensingngnnnnnnngggg:::: frfrfrfromom llllllarargegeggg - ttttttststraraininii aaaappppppppllililililiilicacacacatiitititititiononononss sss ttototototo aaaacocousuuususuussuuuususuu titittttttt c em1010.04.4.220202022202020202002022022222222220222 1919199 NiNiNichcheses oof fibeberoroptptt11717 sssision mooooooononnoonononooooononiitititititititittititororrororororiiiiinininnininingggggg
Distributed acoustic sensing (DAS)Coherent vs. Incoherent detection
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring18
μPosition
Bac
ksca
tter
Int
ensi
ty
FiberOTDR
Pulse propagation
OTDR• Incoherent pulsed light source• Detects overall amount (amplitude)
of light reflected from scattering centers at given fiber position
C-OTDR• Coherent pulsed light source• Detects superposition (interference)
of light reflected from scattering centres at given fibre position
μ Position
Bac
ksca
tter
Int
ensi
ty
FiberC-OTDR
Pulse propagation
Distributed acoustic sensing (DAS)
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring19
Highly-dynamic strain (vibration) measurement• Acquisition rate up to 100 kHz• Monitoring range up to 80 km• Spatial resolution down to 1 m• Sensitivity down to nanostrains
FiberDAS = REC
Position
Tim
e
Sig
nal I
nten
sity
Frequency
Sig
nal S
pect
ral I
nten
sity
Tim
e
FFT
Distributed acoustic sensing (DAS)Applications
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring20
Monitoring of large/extended structures
http:/powerspecialties.comp /p p
Stajanca et al., Sensors 18 (2018), 2841.
Distributed acoustic sensing (DAS)Applications
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring21
Monitoring of large/extended structures
Liehr et al., Opt. Express 26 (2018), 10573-10588.
Distributed acoustic sensing (DAS)Applications
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring22
NWD-relevant applications• Perimeter control (third-party intrusion)• Seismic/geological monitoring
https://openpr.com
By Idobi, CC 3.0
Daley et al. Geophys. Prospect. 64 (2016) 1318-34.
VSP checkshot
Cox et al., CSEG Recorder 2 (2012) 7-13.
2D/3D VSP imaging
Summary
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring23
POFs for strain sensingLarge strain limitEasy integration
• SHM of repository parts
Distributed acoustic sensing (DAS)High-sensitivity vibration measurement
• Repository perimeter control• Repository geological monitoring
Distributed radiation sensingDetection and dosimetry of radiation
• Radiation leak detection• Container radiological profiling
Cox et al., CSEG Recorder 2 (2012) 7-13.By Idobi, CC 3.0
Liehr et al., IEEE Sensors 9 (2009), 1330-1338. Delepine-Lesoille et al., J. Sensors 2012 (2012), 369375.
Acknowledgements
10.04.2019 Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring24
• POLYTEC project consortium
• TRIPOD project consortium
• BAM AGIFAMOR project consortium
• BAM BLEIB project consortium
POD project consortium
THANK YOU FOR YOUR ATTENTION