In this weigh-in-motion(WIM)research,a novel fiber Bragg grating(FBG)-based weigh-in-motion(WIM)system was introduced.The design derived from the idea using in-service bridge abutments as the weigh scale.The bridge be...In this weigh-in-motion(WIM)research,a novel fiber Bragg grating(FBG)-based weigh-in-motion(WIM)system was introduced.The design derived from the idea using in-service bridge abutments as the weigh scale.The bridge beam was replaced by a piece of steel plate which supports the weight of the traveling vehicle.All weights would be finally transferred into the tubes where four FBGs were attached and could record the weight-induced strains by shifting their Bragg wavelengths.The system identification algorithm based on parameters estimation was initiated.Over 40-ton load had been applied on the system and the experimental results showed a good repeatability and linearity.The system resolution had been achieved as low as 10 kg.Compared with other designs of fiber-optic WIM systems,this design is easy and reliable.展开更多
Through analyzing theoretically the temperature effect of the optical-fiber Raman backscattering,a distributed temperature sensor is designed based on the single-mode fiber. Demodulation methods of temperature transdu...Through analyzing theoretically the temperature effect of the optical-fiber Raman backscattering,a distributed temperature sensor is designed based on the single-mode fiber. Demodulation methods of temperature transduction are compared,and then the demodulation method using the ratio of the anti-Stokes and the Stokes Raman backscattering intensity is adopted. Both the hardware composition and the software realization of the system are introduced in detail. The experiment shows that the distinguishing ability of the temperature and that of the space are 1℃ and 2m,respectively,and that the system response time is about 180 s with a sensing range of 5km and with a temperature measurement range of 0-100℃.展开更多
To overcome the invalid phase and phase jump phenomenon generated during the phase unwrapping, a phase error correction method based on the Gaussian filtering algorithm and intensity variance is proposed in this paper...To overcome the invalid phase and phase jump phenomenon generated during the phase unwrapping, a phase error correction method based on the Gaussian filtering algorithm and intensity variance is proposed in this paper. First, a threshold of fringe intensity variance is set to identify and clear the phase in the invalid region. Then, the Gaussian filtering algorithm is employed to correct the phase order at the fringe junction, and then the absolute phase is corrected. Finally, the phase correction experiments of different geometric objects are carried out to verify the feasibility and accuracy of the proposed method. The method proposed in this paper can be extended to the correction of absolute phase error obtained by any coding method.展开更多
In this paper, to reduce the non-linear phase error caused by gamma effect of the digital projector, a novel phase difference extraction method is proposed. First, through multi-layer discrete wavelet decomposition(DW...In this paper, to reduce the non-linear phase error caused by gamma effect of the digital projector, a novel phase difference extraction method is proposed. First, through multi-layer discrete wavelet decomposition(DWT), the components of the original phase difference at different frequencies are extracted. Subsequently, the effective components are taken by the orthogonal matching pursuit(OMP) algorithm, and the phase difference is reconstructed. According to the upper and lower envelopes of the original phase difference extracted by cubic spline interpolation, the residual threshold of OMP is set. According to the results of three-dimensional(3-D) reconstruction experiment on a standard sphere, the proposed method is capable of reducing the errors in the original phase difference and achieving a better imaging result.展开更多
To achieve the real-time detecting and localization of hypervelocity impact events,a monitoring and localization system was designed based on fiber Bragg grating(FBG)sensor network.First,the simulation model was built...To achieve the real-time detecting and localization of hypervelocity impact events,a monitoring and localization system was designed based on fiber Bragg grating(FBG)sensor network.First,the simulation model was built to study the damage evolution and wave propagation process.Subsequently,based on the response mechanism of FBG to strain,the corresponding high frequency demodulation system was designed.Furthermore,a hypervelocity impact experiment was performed to verify the effectiveness of the designed system.Finally,combined with the diamond sensor array localization algorithm,the accurate position of hypervelocity impact source can be achieved.展开更多
文摘In this weigh-in-motion(WIM)research,a novel fiber Bragg grating(FBG)-based weigh-in-motion(WIM)system was introduced.The design derived from the idea using in-service bridge abutments as the weigh scale.The bridge beam was replaced by a piece of steel plate which supports the weight of the traveling vehicle.All weights would be finally transferred into the tubes where four FBGs were attached and could record the weight-induced strains by shifting their Bragg wavelengths.The system identification algorithm based on parameters estimation was initiated.Over 40-ton load had been applied on the system and the experimental results showed a good repeatability and linearity.The system resolution had been achieved as low as 10 kg.Compared with other designs of fiber-optic WIM systems,this design is easy and reliable.
基金Shandong Province Natural Science Foundation (No.Z2006G06)The Excellent Youth Scientist Award Foundation of Shandong Province (No.2006 BS 01001)
文摘Through analyzing theoretically the temperature effect of the optical-fiber Raman backscattering,a distributed temperature sensor is designed based on the single-mode fiber. Demodulation methods of temperature transduction are compared,and then the demodulation method using the ratio of the anti-Stokes and the Stokes Raman backscattering intensity is adopted. Both the hardware composition and the software realization of the system are introduced in detail. The experiment shows that the distinguishing ability of the temperature and that of the space are 1℃ and 2m,respectively,and that the system response time is about 180 s with a sensing range of 5km and with a temperature measurement range of 0-100℃.
基金supported by the National Natural Science Foundation of China(Nos.61873333 and 61903225)the Fundamental Research Funds of Shandong University in China(No.2018JCG06)+3 种基金the Shandong Provincial Natural Science Foundation in China(Nos.ZR2017PEE023 and ZR2017BF007)the National Key Research and Development Project(No.2018YFE02013)the Key Research and Development Plan of Shandong Province(No.2019TSLH0301)the Young Scholars Program of Shandong University(No.2016WLJH30)。
文摘To overcome the invalid phase and phase jump phenomenon generated during the phase unwrapping, a phase error correction method based on the Gaussian filtering algorithm and intensity variance is proposed in this paper. First, a threshold of fringe intensity variance is set to identify and clear the phase in the invalid region. Then, the Gaussian filtering algorithm is employed to correct the phase order at the fringe junction, and then the absolute phase is corrected. Finally, the phase correction experiments of different geometric objects are carried out to verify the feasibility and accuracy of the proposed method. The method proposed in this paper can be extended to the correction of absolute phase error obtained by any coding method.
基金This work has been supported by the National Natural Science Foundation of China(No.61873333)the Fundamental Research Funds of Shandong University in China(No.2018JCG06)+3 种基金the Shandong Provincial Natural Science Foundation of China(Nos.ZR2017PEE023 and ZR2017BF007)the National Key Research and Development Project(No.2018YFE02013)the Key Research and Development Plan of Shandong Province(No.2017CXGC0610)the Young Scholars Program of Shandong University(No.2016WLJH30).
文摘In this paper, to reduce the non-linear phase error caused by gamma effect of the digital projector, a novel phase difference extraction method is proposed. First, through multi-layer discrete wavelet decomposition(DWT), the components of the original phase difference at different frequencies are extracted. Subsequently, the effective components are taken by the orthogonal matching pursuit(OMP) algorithm, and the phase difference is reconstructed. According to the upper and lower envelopes of the original phase difference extracted by cubic spline interpolation, the residual threshold of OMP is set. According to the results of three-dimensional(3-D) reconstruction experiment on a standard sphere, the proposed method is capable of reducing the errors in the original phase difference and achieving a better imaging result.
基金supported by the National Natural Science Foundation of China(No.61873333)the National Key Research and Development Project(No.2018YFE02013)。
文摘To achieve the real-time detecting and localization of hypervelocity impact events,a monitoring and localization system was designed based on fiber Bragg grating(FBG)sensor network.First,the simulation model was built to study the damage evolution and wave propagation process.Subsequently,based on the response mechanism of FBG to strain,the corresponding high frequency demodulation system was designed.Furthermore,a hypervelocity impact experiment was performed to verify the effectiveness of the designed system.Finally,combined with the diamond sensor array localization algorithm,the accurate position of hypervelocity impact source can be achieved.
