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Experiment on dynamic response of fiber optic Fabry-Perot sensors and its application in structural health monitoring

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World Forum on Smart Materials and Smart structures Technology, SMSST 07

作者： Zhang, Wentao Dai, Jingyun Sun, Baochen Du, Yanliang Key Lab. of Structure Health Monitoring and Control of Hebei Province Shijiazhuang Railway Institute Shijiazhuang Hebei China State Key Laboratory on Integrated Optoelectronics Institute of Semiconductors Chinese Academy of Sciences Beijing China

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A novel fiber optic concrete sensor based on EFPI

A novel fiber optic concrete sensor based on EFPI

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International Conference on Smart Materials and Nanotechnology in Engineering

作者： Zhang, Wentao Dai, Jingyun Sun, Baochen Du, Yanliang Key Lab. of Structure Health Monitoring and Control of Hebei Province Shijiazhuang Railway Institute Shijiazhuang Hebei 050043 China State Key Laboratory on Integrated Optoelectronics Institute of Semiconductors Chinese Academy of Sciences Beijing 100083

ISBN: (纸本)9780819465368

In this paper, a novel fiber optic concrete sensor based on extrinsic fiber Fabry-Perot interferometer (EFPI) is designed and analyzed. Two fiber ends are inserted into a glass capillary and encapsulated into a cement cylinder to act as the sensor head. In this way, the cement cylinder itself is the sensor head instead of the traditional steel tube, which makes it very convenient to embed the sensor head into the concrete, because the cement consists with the concrete well. Based on the theory of white light interferometry and the theory of elasticity, the wavelength modulation method and the strain transfer are analyzed theoretically. The demodulation system is also introduced in this paper. The experiment being made by our research group is aimed at testing the consistency, stability, reliability and the sensitivity of the fiber optic sensor. The sensor head of the cement cylinder is embedded into a model ferroconcrete beam together with traditional strain gauges. The experiment is carried out using the PEM-500A hydraulic pulsation fatigue test machine after 2 million stress circles. The readout of the fibre optic sensor and the strain gauges is recorded and made a contrast. It can be found from the result that the fibre optic sensors have good stability and reliability, the accuracy for the fibre optic sensor is better than 0.5 micro-strain, which shows that the sensor can meet the demand of the long-term monitoring of large-size concrete structure.

关键词： Fiber optic sensors

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Analysis on strain transfer of fiber optic Fabry-Perot sensors-based on FEM method

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World Forum on Smart Materials and Smart structures Technology, SMSST 07

作者： Zhang, Wentao Dai, Jingyun Sun, Baochen Du, Yanliang Key Lab. of Structure Health Monitoring and Control ofHebei Province Shijiazhuang Railway Institute Shijiazhuang Hebei China State Key Laboratory on Integrated Optoelectronics Institute of Semiconductors Chinese Academy of Sciences Beijing China

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Study on Influence of Crack on the Blade Status Using FBGs

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Photonic Sensors 2018年第1期8卷 63-69页

作者： Gang XU Lei LIANG Jianzhi LI Huaping MEI Hongli LI Yijun LIU National Engineering Laboratory of Fiber Optic Sensing Technology Wuhan University of Technology Wuhan 430070 China The Key Laboratory for Health Monitoring and Control of Large Structures Shijiazhuang 050043 China School of Mechanical Engineering Hubei Engineering University Xiaogan 432000 China

The status detection for rotating parts is difficult since the sensor is influenced by the rotation in the inflammable, explosive, and strong magnetic environment. Based on the fiber Bragg grating sensing technology, this paper studies the influence of the natural frequency and deformation of a rotor blade affected by the size of crack in the blade. Test results show that the speed of the equipment and blade excited vibration frequency are two main factors or deformation and vibration frequency of the blade. With an increase in the crack depth, the blade deformation is increased while the stimulated natural frequency of the blade is decreased; at a low rotational speed, the deformation is mainly caused by the rotating speed of the blade. On the contrary, the vibration blade itself contributes to the deformation at a high speed. During the process of full speed rotation, the influence of the rotational speed on the blade deformation almost remains the same, and the influence of the natural vibration on blade deformation is increased with an increase in the rotational speed.

关键词： Rotor blade fiber Bragg grating crack depth rotational speed blade frequency blade deformation

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Experimental study on wind pressure distribution and wind-induced interference effects on long-span spherical structure

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Jianzhu Jiegou Xuebao/Journal of Building structures 2016年第10期37卷 140-146页

作者： Liu, Qingkuan Lu, Zhaoliang Zheng, Yunfei Ma, Wenyong Liu, Xiaobing Structural Health Monitoring and Control Institute Shijiazhuang Tiedao University Shijiazhuang050043 China Key Laboratory for Structure Health Monitoring and Control in Hebei Province Shijiazhuang050043 China School of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China

Spherical shell structure is very sensitive to wind loads. The wind load is one of the most important loads in structural design. By wind tunnel tests, simultaneous multi-pressure measurement on surface of spherical shell structure was carried out under different conditions to study the characteristics of wind load distribution and wind-induced interference effects. Results show that opened and closed sunroofs have significant effect on wind pressure distribution on the outer surface of the structure in partial region, especially, leeward side. For the inner surface of the structure, wind pressure become small when sunroof is closed, which is safe for the outer structure. Coal dump has no effect on wind pressure distribution along wind direction, while in cross wind direction it has effect. Different relative positions of adjacent structures have certain influence on wind-induced interference effects and different regions have different effects. © 2016, Editorial Office of Journal of Building structures. All right reserved.

关键词： Wind stress

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Structure crack monitoring based on long-gauge FBG sensor 2nd

Structure crack monitoring based on long-gauge FBG sensor

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2nd International Conference of Structural health monitoring and Integrity Management, ICSHMIM 2014

作者： Zhang, Wentao Li, Fang Lin, Huang Ce, Bian Xu, Hongbin Du, Yanliang Optoelectronic System Laboratory Institute of Semiconductors Chinese Academy of Sciences Beijing China Graduate School of Shijiazhuang Tiedao University Shijiazhuang China Key Lab of Structure Health Monitoring and Control of Hebei Province Shijiazhuang Tiedao University Shijiazhuang China

ISBN: (纸本)9781138027763

Crack detection is very important for long-term large-scale structural health monitoring (SHM). Fiber optic sensor has been approved to have good performance in application in SHM. In this paper, we present a novel method to monitor the crack by using long-gauge FBG sensor. A FBG with a gauge length of 50 mm is fabricated. When the crack pass through the FBG, the reflect spectrum of FBG will be expanded or chipped. Different position of the crack will result in different shape of the spectrum. By analyzing the characteristics of the spectrum, the position of the crack can be detected and the opening width of the crack can be estimated. © 2015 Taylor & Francis Group, London.

关键词： Structural health monitoring

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Main Structure Design and Constructional Safety control of large-span Gravel Surrounding-Rock Tunnel

Main Structure Design and Constructional Safety Control of L...

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作者： Li De-kang Li Hao-ran OuYang Zuo-lin Yue Zhi-guo Dong Yan-dong Structural Health Monitoring and Control Institute Shijiazhuang Tiedao University The Key Laboratory for Health Monitoring and Control of Large Structures Shijiazhuang Tiedao University Shuohuang Railway Development Limited Liability Company

As the construction of large-span gravel surrounding-rock tunnel is very difficult which has serious security risks,it is significant to choose a set of reasonable structure design methods and safety control *** paper taked a large-span gravel road tunnel in Jinan Expressway as an *** combining theoretical analysis with numerical simulation,the main structure design process of the large-span IV level surrounding-rock tunnel was divided into four steps,meanwhile concrete measure basis and testing methods were *** to the engineering geological conditions and the structure design schemes,the construction schemes and monitoring measurement projects of large-span gravel surrounding-rock tunnel were determined to ensure the safety of tunnel *** paper provides a complete example scheme for the design and construction of the main structure of the large-span IV class surrounding-rock tunnel,which provides a reference for similar projects in the future.

关键词： IOP Main Structure Design and Constructional Safety control of large-span Gravel Surrounding-Rock Tunnel

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Analysis on GPR echo signal enhancement algorithm based on subspace sparsity deconvolution

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Journal of Engineering Science and Technology Review 2016年第6期9卷 43-51页

作者： Yong, Yang Yanliang, Du Weigang, Zhao Baoxian, Wang Hao, Zhao School of Mechanical Electronic and Control Engineering Beijing Jiaotong University Beijing100044 China The Key Laboratory for Health Monitoring and Control of Large Structures in Hebei Province Shijiazhuang Tiedao University Shijiazhuang050043 China Department of Urban and Civil Engineering Ibaraki University Hitachi316-8511 Japan

Strong reflection interference of rebar is the main barrier against ground-penetrating radar (GPR) detection of internal diseases in reinforced concrete structure. Deconvolution can strengthen GPR echo data through acquiring structural layer data. However, existing deconvolution echo signal processing algorithms cannot be applied to process the GPR echo data because of the hypothesis that the wavelet is in the minimum phase system, which is inconsistent with the attenuation of GPR wavelet during two-way travel time. To resolve this problem, a new subspace sparsity deconvolution algorithm was proposed in this paper to enhance the echo signal of rebar lower diseases. A wavelet signal attenuation model of layered structure was firstly established to analyse the influencing factors of disease echo signal attenuation under different conditions. On this basis, the sparsity deconvolution algorithm based on wavelet iteration was placed to enhance GPR echo signal quickly by using the constraint condition of subspace errors. The processing of GPR forward simulation data also reveals that the proposed algorithm can inhibit noises effectively and acquire layer information from the concrete structure when the local signal-to-noise ratio is larger than -19.7dB. The proposed algorithm is clearly superior to the existing automatic gain control algorithm with respect to the echo enhancement effect of GPR. Results show that this method overcomes the minimum phase restriction of deconvolution and it is of great significance to detect and recognize inter-layer diseases of high-speed railway ballastless tracks. © 2016 Eastern Macedonia and Thrace Institute of Technology. All rights reserved.

关键词： Concrete construction

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A Novel Rough-Surface Direct Wave Suppression Algorithm b ased on Energy Adaptive Analysis

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Journal of Engineering Science and Technology Review 2016年第4期9卷 202-208页

作者： Yong, Yang Weigang, Zhao Yanliang, Du Hao, Zhang School of Mechanical Electronic and Control Engineering Beijing Jiaotong University Beijing100044 China The Key Laboratory for Health Monitoring and Control of Large Structures in Hebei Province Shijiazhuang Tiedao University Shijiazhuang050043 China Department of Urban & Civil Engineering Ibaraki University Hitachi 316-8511 Japan

As a nondestructive testing technology, ground penetrating radar (GPR) is widely used in the detection and recognition of high-speed railway subgrade diseases. Rough-surface direct wave suppression caused by locomotive vibration and subgrade irregularity is a challenge in the GPR signal process. Flat-surface assumption makes traditional method difficult to apply directly to the rough terrain environment. To remove rough-surface direct wave and improve the signal-to-noise ratio, a new adaptive algorithm is proposed in this paper. First, according to the characteristic of electromagnetic wave propagation, the echo model of GPR was constructed, and the composition of ground radar echo signal was analyzed. Next, the eigenvalue and eigenvector of the echo signal and ground direct wave were studied. With the increase of relative permittivity, the energy eigenvector of direct wave and echo signal converged to the same vector space. On this basis, a rough-surface direct wave suppression framework based on energy feature adaptive analysis was proposed. Finally, a numerical simulation and field experiment were carried out to verify the feasibility of the algorithm. Results showed that the algorithm effectively suppresses the rough ground direct wave, and the processing result preserves the target echo more completely. Without intervention, this method can be applied in automatic direct wave suppression, which will promote the development of automatic identification technology in the detection of railway subgrade diseases. © 2016. Eastern Macedonia and Thrace Institute of Technology. All rights reserved.

关键词： Vector spaces

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THE INTERNAL CRACK IN PIEZOELECTRICPIEZOMAGNETIC SANDWICHED STRUCTURE UNDER IN-PLANE COUPLE LOADING

THE INTERNAL CRACK IN PIEZOELECTRICPIEZOMAGNETIC SANDWICHED ...

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2016年全国压电和声波理论及器件应用研讨会

作者： Xing ZHAO Jin-xi LIU Zheng-hua QIAN Department of Engineering Mechanics/The Key Laboratory for Health Monitoring and Control of Large Structures Shijiazhuang Tiedao University State Key Laboratory of Mechanics and Control of Mechanical Structures/College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics

Background, Motivation and Objective The piezoelectric-piezomagnetic(PE-PM) sandwiched structures are consisted of layered piezoelectric and piezomagnetic materials. They are easy to be manufactured and possess superior magnetoelectric(ME) coupling effect. With these superiorities, the PE-PM sandwiched structures have been widely used in sensors, transducers and acoustic wave devices and so on. However, due to the fragility of the materials and complicated in-service loading conditions, the PE-PM sandwiched structures tend to fracture easily. So, it is essential to research the internal crack in PE-PM sandwiched structures under electro-magneto-mechanical coupled loadings. However, up until now, there is no paper studies the mode-I crack in PE-PM-PE sandwiched structure under in-plane electro-mechanical coupled loading. From the above, considering the magnetic field of piezoelectric material and the electric field of piezomagnetic material, a mode-I internal crack problem of a PM layer bonded to two PE layers is studied in this paper. Statement of Contribution/Methods This paper contributes to obtaining an analytical solution by using the integral transform technique. Firstly, the Fourier transforms are applied to the governing equations, and a set of appropriate solutions are obtained with some unknown functions. Then, substituting the appropriate solutions into boundary conditions meanwhile considering the magnetoelectric permeable crack plane conditions, we could derive the dual integral equations after the complex mathematical process. In order to obtain the magneto-electro-elastic field in the near of the crack tip, the dual integral equations are reduced into the singular integral equations with Cauchy kernel of the second kind. Finally, the Cauchy singular integral equations will be solved by Gauss-Jacobi collocation method. Meanwhile, the field intensity factors(FIFs) could be obtained. Results In this paper, an integral transform technique is employed to re

关键词： Mode I crack Piezoelectric-piezomagnetic sandwiched structure Field intensity factors Cauchy singular integral equation

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