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Research On Optical Fiber Grating Sensing Test To Simulation Experiments

Posted on:2005-11-30Degree:MasterType:Thesis
Country:ChinaCandidate:S M WeiFull Text:PDF
GTID:2168360125958211Subject:Mining engineering
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The optical fiber sensing is a new developing technology. For the peculiar merits, it has been concerned by more and more people and applied in many domains. The optical fiber sensor can be used to monitor materials' deformation and locate it when the layout is distributed.By testing the intensity of light, phase, polarization and wavelength (or frequency), the monitoring or measuring to external can be achieved. This is the basic principle of optical fiber sensing technology. The optical fiber sensor is a kind of device which can monitor change of external environment by testing the characteristics of light. It is based on light transmission in fiber. The optical fiber grating technology develops fast. The grating can filter signal and permit light with certain wavelength to pass through, and the signal will be reflected which can't go. The change of the strain and temperature will cause wavelength drift. Assume the temperature to be constant, the strain can be gotten measuring wavelength drift.In this paper, with bending loss of optical fiber, deformation of rock layer can be monitored. The subsidence of rock makes embedded sensor deform, and so, the loss varies. Keep link sides stable, the loss is only attributed to deformation. The result indicates that, in initial stage of mining, the fiber loss increases with rock not moving. When the rock layer has small deformation, loss decreases, and the change range becomes small before falling. Other experiments have the same results. With this method, the location of deformation can't be defined although the loss varies with it. So, in later experiments, the optical fiber grating technology is chosen.The optical fiber gratings are embedded in. The variety of fiber strain attributed to rock subsidence makes wavelength drift. In experiment, the drifts are accordant of the gratings in the same location. Near mining, the wavelength drifts firstly. Ahead of face10~30cm, the abutment pressure distributes again, and the wavelength increases. The elastic deformation of the rock can be measured by grating. The feasibility of testing rock deformation by the optical fiber grating technology is verified in this paper. The drift can reflect the deformation.
Keywords/Search Tags:optical fiber sensor, simulation experiment, bending loss, optical fiber grating, wavelength drift
PDF Full Text Request
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