scholarly journals A Highly Integrated BOTDA/XFG Sensor on a Single Fiber for Simultaneous Multi-Parameter Monitoring of Slopes

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2132 ◽  
Author(s):  
Feng Li ◽  
Weigang Zhao ◽  
Hongbin Xu ◽  
Shupeng Wang ◽  
Yanliang Du
Keyword(s):  
Brillouin Scattering ◽  
Surface Displacement ◽  
Single Fiber ◽  
Dynamic Strain ◽  
Fiber Grating ◽  
Distributed Sensor ◽  
Discrete Dynamic ◽  
Sensing Technology ◽  
Period Fiber Grating ◽  
Stimulated Brillouin

A highly integrated sensing technology, combining a stimulated Brillouin scattering-based distributed sensor with XFG (fiber Bragg grating (FBG) and long-period fiber grating (LPFG)) sensors on a single fiber, is proposed for the simultaneous measurement of fully distributed and multiple discrete dynamic strains/temperatures. A multiparameter monitoring scheme for slope safety is developed using this integrated sensing technology. An indoor simulation test is carried out to verify its ability to simultaneously monitor a slope’s surface displacement, an anchor reinforcement’s axial force, and rockfall vibration. The experimental results show that distributed static strain and discrete dynamic strain can be well-measured simultaneously with little interference. The results also demonstrate the XFG sensors’ capability for multi-type and multipoint multiplexing. In addition, the proposed hybrid sensor system has potential for the monitoring of multiple slope parameters simultaneously.

scholarly journals Dynamic Responses Measured by Optical Fiber Sensor for Structural Health Monitoring

2019 ◽  
Vol 9 (15) ◽  
pp. 2956 ◽  
Author(s):  
Shiuh-Chuan Her ◽  
Shin-Chieh Chung
Keyword(s):  
Optical Fiber ◽  
Dynamic Strain ◽  
Fiber Grating ◽  
Base Excitation ◽  
Long Period ◽  
Fiber Sensing ◽  
Fbg Sensor ◽  
Sensing System ◽  
Optical Fiber Sensing ◽  
Period Fiber Grating

An optical fiber sensing system integrating a fiber Bragg grating (FBG) sensor, a long-period fiber grating (LPFG) optical filter and a photodetector is presented to monitor the dynamic response of a structure subjected to base excitation and impact loading. The FBG sensor is attached to a test specimen and connected to an LPFG filter. As the light reflected from the FBG sensor is transmitted through the long-period fiber grating filter, the intensity of the light is modulated by the wavelength, which is affected by the strain of the FBG. By measuring the intensity of the light using a photodetector, the wavelength reflected from the FBG sensor can be demodulated, thus leading to the determination of the strain in the structure. To demonstrate its effectiveness, the proposed sensing system was employed to measure the dynamic strain of a beam subjected to mechanical testing. The mechanical tests comprised three load scenarios: base excitation by a shaker at resonant frequency, impact loading by a hammer and shock test on a drop table. To monitor the dynamic strain during the test and validate the accuracy of the measurement of the FBG sensor, strain gauge was used as reference. Experimental results show good correlation between the measurements of FBG sensor and strain gauge. The present work provides a fast response and easy-to-implement optical fiber sensing system for structural health monitoring based on real-time dynamic strain measurements.

scholarly journals Application of FBG Sensing Technology to Internal Deformation Monitoring of Landslide

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Haiyou Peng ◽  
Bolin Chen ◽  
Ping Dong ◽  
Si chen ◽  
Yunping Liao ◽  
...  
Keyword(s):  
Slip Surface ◽  
Survey Methods ◽  
Surface Displacement ◽  
Deformation Monitoring ◽  
In Situ Monitoring ◽  
Fiber Grating ◽  
Monitoring Point ◽  
Sensing Technology ◽  
Internal Deformation

Limited by geological survey methods, processes, and cost, it has long been a difficult thing to accurately detect the position of landslide slip surface and monitor the landslide internal deformation. Fiber Bragg grating (FBG) sensing technology has been widely used in geological engineering and geotechnical engineering due to its high-precision property. In this research, FBG sensing technology was applied to the monitoring of landslide internal deformation in Toudu, Chongqing, China. The in situ monitoring by FBG accurately determined the position of the landslide slip surface. Based on the relationship between fiber grating strain and deflection, the formula between landslide internal deformation and fiber grating strain was obtained, and the rationality of the formula was verified by the monitoring data of surface displacement. Finally, the internal deformation at the monitoring point of the Toudu landslide was calculated and the mechanism of the landslide was analyzed.

scholarly journals Dynamic Strain Measurement Using Small Gain Stimulated Brillouin Scattering in STFT-BOTDR

2017 ◽  
Vol 17 (9) ◽  
pp. 2718-2724 ◽  
Author(s):  
Bo Li ◽  
Linqing Luo ◽  
Yifei Yu ◽  
Kenichi Soga ◽  
Jize Yan
Keyword(s):  
Strain Measurement ◽  
Brillouin Scattering ◽  
Stimulated Brillouin Scattering ◽  
Dynamic Strain ◽  
Small Gain ◽  
Stimulated Brillouin
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