Optical fibre sensor has the advantages of small size,light weight,anti⁃electromagnetic interference,and high measurement accuracy,which has important applications in research and industrial production.To design an op...Optical fibre sensor has the advantages of small size,light weight,anti⁃electromagnetic interference,and high measurement accuracy,which has important applications in research and industrial production.To design an optical fibre displacement sensor(OFBDS)with simple structure and high measurement accuracy,the unified model of the commonly used OFBDS structures was proposed and the feasibility of the intensity⁃modulation of multi⁃structural optical fibre bundles was analysed based on the arrangement characteristics of the fibre bundle end⁃face.The intensity⁃modulation characteristic of different fibre bundles was analysed,and the single coil coaxial fibre bundle was chosen as the fibre probe in this study.The sensor hardware system was designed.Lastly,the calibration experiment,temperature interference experiment,changes of measured plane surface area,and the dynamic experiment were conducted.Results showed that the sensor linear measurement range was about 3 mm,and the sensor system had excellent static and dynamic characteristics.展开更多
Optical fibre sensors based on Brillouin scattering have been vigorously studied in the context of structural health monitoring on account of their capacity for distributed strain and temperature measurements.However,...Optical fibre sensors based on Brillouin scattering have been vigorously studied in the context of structural health monitoring on account of their capacity for distributed strain and temperature measurements.However,real-time distributed strain measurement has been achieved only for two-end-access systems;such systems reduce the degree of freedom in embedding the sensors into structures,and furthermore render the measurement no longer feasible when extremely high loss or breakage occurs at a point along the sensing fibre.Here,we demonstrate real-time distributed measurement with an intrinsically one-end-access reflectometry configuration by using a correlation-domain technique.In this method,the Brillouin gain spectrum is obtained at high speed using a voltage-controlled oscillator,and the Brillouin frequency shift is converted into a phase delay of a synchronous sinusoidal waveform;the phase delay is subsequently converted into a voltage,which can be directly measured.When a single-point measurement is performed at an arbitrary position,a strain sampling rate of up to 100 kHz is experimentally verified by detecting locally applied dynamic strain at 1 kHz.When distributed measurements are performed at 100 points with 10 times averaging,a repetition rate of 100 Hz is verified by tracking a mechanical wave propagating along the fibre.Some drawbacks of this ultrahigh-speed configuration,including the reduced measurement accuracy,lowered spatial resolution and limited strain dynamic range,are also discussed.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.51775260)the Qinglan Project of Jiangsu Province(2017)of China and the Funds of Nanjing Institute of Technology(Grant No.CKJA201801).
文摘Optical fibre sensor has the advantages of small size,light weight,anti⁃electromagnetic interference,and high measurement accuracy,which has important applications in research and industrial production.To design an optical fibre displacement sensor(OFBDS)with simple structure and high measurement accuracy,the unified model of the commonly used OFBDS structures was proposed and the feasibility of the intensity⁃modulation of multi⁃structural optical fibre bundles was analysed based on the arrangement characteristics of the fibre bundle end⁃face.The intensity⁃modulation characteristic of different fibre bundles was analysed,and the single coil coaxial fibre bundle was chosen as the fibre probe in this study.The sensor hardware system was designed.Lastly,the calibration experiment,temperature interference experiment,changes of measured plane surface area,and the dynamic experiment were conducted.Results showed that the sensor linear measurement range was about 3 mm,and the sensor system had excellent static and dynamic characteristics.
基金supported by JSPS KAKENHI Grant Numbers 25709032,26630180 and 25007652by research grants from the Iwatani Naoji FoundationSCAT Foundation and the Konica Minolta Science and Technology Foundation.
文摘Optical fibre sensors based on Brillouin scattering have been vigorously studied in the context of structural health monitoring on account of their capacity for distributed strain and temperature measurements.However,real-time distributed strain measurement has been achieved only for two-end-access systems;such systems reduce the degree of freedom in embedding the sensors into structures,and furthermore render the measurement no longer feasible when extremely high loss or breakage occurs at a point along the sensing fibre.Here,we demonstrate real-time distributed measurement with an intrinsically one-end-access reflectometry configuration by using a correlation-domain technique.In this method,the Brillouin gain spectrum is obtained at high speed using a voltage-controlled oscillator,and the Brillouin frequency shift is converted into a phase delay of a synchronous sinusoidal waveform;the phase delay is subsequently converted into a voltage,which can be directly measured.When a single-point measurement is performed at an arbitrary position,a strain sampling rate of up to 100 kHz is experimentally verified by detecting locally applied dynamic strain at 1 kHz.When distributed measurements are performed at 100 points with 10 times averaging,a repetition rate of 100 Hz is verified by tracking a mechanical wave propagating along the fibre.Some drawbacks of this ultrahigh-speed configuration,including the reduced measurement accuracy,lowered spatial resolution and limited strain dynamic range,are also discussed.
