Signature of structure failure using asymmetric and broadening factors of Brillouin spectrum

Ravet, Fabien; Bao, Xiaoyi; Ozbakkaloglu, Togay; Saatçioğlu, Murat

doi:10.1109/lpt.2005.862366

Cited by 16 publications

(14 citation statements)

References 6 publications

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“…If local strains or loads are applied on the fiber at position z, the Brillouin spectrum is distorted [20] and several spectral components S e (v) appear. Their central frequencies and amplitude are related to the strains.…”

Section: B Source Separationmentioning

confidence: 99%

Source separation and distributed sensing: The key for an efficient monitoring

Mars

Buchoud

Vrabie

et al. 2013

2013 5th IEEE International Workshop on Computational Advances in Multi-Sensor Adaptive Processing (CAMSAP)

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As a complement to classical sensors, Distributed Optical Fiber Sensors now play a prominent role in several engineering fields and act as an antenna array. Depending of the devices used (Raman, Rayleigh, or Brillouin scattering), measurement record depend on temperature, strain, or pressure profile. As the wanted signal is often hidden by noise and other undesired sources, we can express the problem as a source separation problem. In this paper, we show that with the help of recent techniques based on data decomposition and source separation (PCA, ICA NMF techniques) from the virtual antenna, we can accurately identify water leakages from a noisy Raman spectra or a strain profile from Brillouin spectra with a spatial resolution of 1cm instead of 1 meter for classical devices.

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Section: B Source Separationmentioning

confidence: 99%

Source separation and distributed sensing: The key for an efficient monitoring

Mars

Buchoud

Vrabie

et al. 2013

2013 5th IEEE International Workshop on Computational Advances in Multi-Sensor Adaptive Processing (CAMSAP)

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“…Optical fibers can cover large areas of civil structures and access the safety and status of the structures. This kind of sensor has the advantages of a long sensing range and the capability of providing strain or temperature at every spatial resolution over entire sensing fiber imbedded in or attached to the structures by using fiber itself as sensing medium [58,59].…”

Section: Structural Health Monitoring With Distributed Sensor Based Omentioning

confidence: 99%

“…the structure responds to the load linearly with average strain over the spatial resolution being monitored [59]. The extraction of average strain is carried with single peak fitting or centroid method (integrated spectrum area method) [58][59][60][61]. Those methods provide fast signal processing to identify large strain points, while multiple peak detection [62] provides better strain accuracy with a compromise of long processing time which makes it difficult for dynamic detection and disaster prevention.…”

Section: Structural Health Monitoring With Distributed Sensor Based Omentioning

confidence: 99%

“…The first few civil structural applications were under elastic working region with the purpose of verifying distributed Brillouin sensor for strain monitoring, in which no deformation happened during loading process. Most of recent research on distributed sensor has been focused on using distributed Brillouin sensor as a tool to correlate the strains to civil structural condition, such as cracks and deformation [57][58][59][60][61][62], as well as prediction of cracking of concretes and buckling in pipelines using special signal processing schemes via detailed studies of Brillouin spectrum shape change, such as asymmetry broadening in addition to peak change [57,63], as well as cure monitoring of composite materials [64].…”

Section: Structural Health Monitoring With Distributed Sensor Based Omentioning

confidence: 99%

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Recent progress in optical fiber sensors based on Brillouin scattering at university of Ottawa

Bao

Chen

2011

Photonic Sens

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The distributed sensor is proven to be a powerful tool for civil structural and material process monitoring. Brillouin scattering in fiber can be used as point sensors or distributed sensors for measurement of temperature, strain, birefringence and vibration over centimeters (Brillouin grating length) for point sensor or the pulse length for the distributed sensor. Simultaneous strain and temperature measurement with a spatial resolution of 20 cm is demonstrated in a Panda fiber using Brillouin grating technique with the temperature accuracy and strain accuracy of 0.4 ℃ and 9 µε. This technique can also be used for distributed birefringence measurement. For Brillouin optical time domain analysis (BOTDA), we have developed a new technique to measure differential Brillouin gain instead of Brillouin gain itself. This technique allows high precision temperature and strain measurement over long sensing length with sub-meter spatial resolution: 50-cm spatial resolution for 50-km length, using return-to-zero coded optical pulses of BOTDA with the temperature resolution of 0.7 ℃, which is equivalent to strain accuracy of 12 µε. For over 50-km sensing length, we proposed and demonstrated frequency-division-multiplexing (FDM) and time-division-multiplexing (TDM) based BOTDA technique for 75-km and 100-km sensing length without inline amplification within the sensing length. The spatial resolution of 2 m (100 km) and Brillouin frequency shift accuracy of 1.5 MHz have been obtained for TDM based BOTDA and 1-m resolution (75 km) with Brillouin frequency shift accuracy of 1 MHz using FDM based BOTDA. The civil structural health monitoring with BOTDA technique has been demonstrated. Distributed fiber sensors based on Brillouin scatteringFor over two decades, distributed optical fiber sensors based on Brillouin scattering have gained much interest for their potential capabilities of monitoring temperature [1] and strain [2] in civil and structural engineering, environmental monitoring, and geotechnical engineering. Brillouin scattering occurs as a result of refractive-index fluctuations caused by acoustic waves resulted from thermally generated sound waves, and such thermal agitation is capable of scattering incident lightwaves with shifted frequencies. Stimulated Brillouin scattering (SBS) enhances the Brillouin scattering in a Brillouin optical time domain analysis (BOTDA) [3][4][5][6][7][8] with intense signal and better spatial resolution comparing with a spontaneous scattering based Brillouin optical time domain reflectometry (BOTDR) [9][10][11]. At present, there are two schemes to realize a BOTDA, including Brillouin gain [3][4][5] and Brillouin loss [6][7][8]. In a Brillouin-gain-based

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“…The device determines automatically the strain profiles thanks to the abscissa of the maximum of the gain curves. Ravet et al (2006) showed that Brillouin gain curves could be distorted by local non uniform strain distribution along the fiber. In this paper, two new factors are defined so as to highlight asymmetry and broadening of the Brillouin gain curves.…”

Section: Introductionmentioning

confidence: 99%

Detection of Ground Movement using the Shape of Brillouin Spectrum

Buchoud

Blairon²,

d'Urso³

et al. 2013

Symposium on the Application of Geophysics to Engineering and Environmental Problems 2013

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Distributed Optical Fiber Sensing systems (DOFSS) are composed by optical fibers wrapped in strain sensing cables, coupled with Brillouin interrogators. DOFSS are increasingly used for Structural Health Monitoring (SHM) as they can provide continuous strain profiles along the optical fiber localized in the structure. Raw Brillouin measurements consist in gain -frequency curves with a Lorentzian shape. Strain is generally assessed thanks to the abscissa of the maximum of the gain curve. Two new factors are introduced. They are sensitive to asymmetry and broadening of the Brillouin gain curve which can highlight strain gradient within the spatial resolution of the interrogator. These parameters could be used to detect more efficiently local events and improve instrument algorithm.

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Signature of structure failure using asymmetric and broadening factors of Brillouin spectrum

Cited by 16 publications

References 6 publications

Source separation and distributed sensing: The key for an efficient monitoring

Source separation and distributed sensing: The key for an efficient monitoring

Recent progress in optical fiber sensors based on Brillouin scattering at university of Ottawa

Detection of Ground Movement using the Shape of Brillouin Spectrum

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