The Application of Improved Genetic Algorithm in Fiber Bragg Grating (FBG) Sensor Network

2008 ◽  
Author(s):  
Wei Wu ◽  
Xin Liu
Keyword(s):  
Genetic Algorithm ◽  
Fiber Bragg Grating ◽  
Sensor Network ◽  
Bragg Grating ◽  
Improved Genetic Algorithm ◽  
Fbg Sensor

Smart Structural Health Monitoring Based on Detecting Picometer-Scale Wavelength Shift of Fiber Bragg Grating

2013 ◽  
Vol 562-565 ◽  
pp. 1346-1352
Author(s):  
Jun Jie Bai ◽  
Jian Xing Li ◽  
Jun Zhang ◽  
Xiao Yun Zhang ◽  
Le Wang ◽  
...  
Keyword(s):  
Fiber Bragg Grating ◽  
Sensor Network ◽  
Health Monitoring ◽  
High Speed ◽  
Smart Structure ◽  
Comb Filter ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Center Wavelength ◽  
Fbg Sensor

The real-time monitoring technologies of smart civil structure based on detecting picometer-scale wavelength shift of fiber Bragg grating (FBG), including the wavelength demodulation technology of FBG, are researched extensively at home and abroad. In the paper, using the technologies of wavelength division multiplex (WDM) and time division multiplex (TDM), fiber Bragg grating (FBG) sensor network was built for monitoring smart structure health condition. Based on SOPC (System on Programmable Chip) technology and fiber comb filter, a high-speed and high-precision wavelength demodulation scheme of FBG sensor network was proposed. The optical system and hardware circuit for demodulation system were designed specifically. To improve the accuracy of demodulation system of FBG, a constant temperature channel of the demodulation system connected with a fiber comb filter, which offered reference points to calibrate the Bragg grating center wavelength. Based on 32-bit soft-core processor NoisⅡ, the embedded system collected and processed the photoelectric signal voltage transformed to rectangular voltage pulse. The upper computer displayed dynamically the FBG wavelength demodulation process and calibrated the Bragg grating center wavelength. The experiments of FBG wavelength demodulation and health monitoring of smart structural embedded fiber Bragg gratings were done. Experimental results show that, the FBG wavelength demodulation method can be used to demodulate the FBG wavelength with high speed and high precision (± 2 pm), which can be used extensively in large-scale multipoint monitor engineering, and the strains of the smart structure can be measured accurately.

Investigation on Temperature Compensation of Fiber Bragg Grating Sensors for Hull Monitoring

2018 ◽  
Author(s):  
Ruiqi Ma ◽  
Guoqing Feng ◽  
Huilong Ren ◽  
Peng Fu ◽  
Shuang Wu ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Fiber Bragg Grating ◽  
Temperature Compensation ◽  
Compensation Method ◽  
Bragg Grating ◽  
Theoretical Derivation ◽  
Temperature Changes ◽  
Hull Girder ◽  
Fbg Sensor ◽  
Fbg Sensors

Hull monitoring system with Fiber Bragg Grating (FBG) sensors increasingly receives people’s attentions. However, for the ship hull monitoring, the deformation of hull girder changes a lot as is subjected to a huge temperature variation. Therefore, the compensation method with only FBG temperature self-correction is not suitable for the hull monitoring sensors because no material thermal expansion effects are reasonably included. In this paper, the new compensation method of hull monitoring FBG sensor based on the sensor theory with both FBG temperature self-correction and steel thermal expansion effects correction is studied. The coupled compensation method suitable for hull monitoring sensor is obtained by theoretical derivation. As the comparison, the coupled compensation experiment was carried out. The results show that the relative error under the temperature compensation method is large in the case of drastic strain and temperature changes, and the correction results of the tested method will be closer to the true level.

The Vibration Analysis of a Novel Vortex Flowmeter Based on Fiber Bragg Grating

2012 ◽  
Vol 485 ◽  
pp. 526-531 ◽  
Author(s):  
Hui Juan Dong ◽  
Yong Cai ◽  
Jun He ◽  
Ren Bing Liu
Keyword(s):  
Fiber Bragg Grating ◽  
Vibration Analysis ◽  
Axial Strain ◽  
Damping Ratio ◽  
Bragg Grating ◽  
Measuring Range ◽  
Fbg Sensor ◽  
Vortex Flowmeter ◽  
Acrylic Glass ◽  
Mass Spring

A novel fiber Bragg grating vortex flowmeter was designed in this work, where the Bragg grating was enfolded in a cylinder eddy generator. Bragg grating subject to force and the corresponding strain were analyzed. Subsequently, the relationships between grating’s axial strain and flow were developed. In order to improve the flowmeter's resolution, the system was simplified by a mass-spring-damper model, which was used to analyze resonance and choose acrylic glass as cylinder's material. In terms of the resolution of FBG sensor demodulation device and factors of vortex's formation, the measuring range of flowmeter is 1200L/h~5000L/h. The resolution is less than 40L/h with flow exceeding 2000L/h. The damping ratio is not sensitive to the flow when it is less than 2000L/h.

Detection of Pipeline Curvature with FBG Sensors Twisted

2013 ◽  
Vol 303-306 ◽  
pp. 67-73 ◽  
Author(s):  
Yan An Zhang ◽  
Zheng Liu ◽  
Lin Yong Shen ◽  
Jin Wu Qian
Keyword(s):  
Fiber Bragg Grating ◽  
Curve Fitting ◽  
Bragg Grating ◽  
Bending Deformation ◽  
Fbg Sensor ◽  
Underground Pipelines ◽  
Fbg Sensors ◽  
Simulation Results ◽  
Spatial Trajectory ◽  
Fitting Accuracy

In trenchless detection of underground pipelines, a method has been introduced which employs Fiber Bragg Grating (FBG) sensors to detect curvatures of the pipeline at discrete points and reconstructs the spatial trajectory of the pipeline by means of a newly developed approach. In measuring the pipeline curvature, the FBG sensor may be twisted besides sustaining bending deformation. This paper proposes a new algorithm for curvature calculation at discrete points, considering both overall revolving and partial twisting of the FBG sensors in order to enhance the curve fitting accuracy. Simulation results verify the effectiveness of the method.

Application of Fiber Bragg Grating Technology in Spacecraft Structural Fault Detection

2019 ◽  
Vol 14 (12) ◽  
pp. 1725-1732
Author(s):  
Xingyu Zheng
Keyword(s):  
Fault Detection ◽  
Fiber Bragg Grating ◽  
Fault Location ◽  
Measurement Model ◽  
Angle Measurement ◽  
Thin Plates ◽  
Bragg Grating ◽  
Structural Failure ◽  
Fbg Sensor ◽  
Structural Problems

With the prolongation of the service life of spacecraft, the structural failure of spacecraft caused by air resistance and aging poses a direct threat to the safe operation of spacecraft. The structural failure of aircraft is concerned by many researchers. Among them, the fiber Bragg grating (FBG) sensor has become a hotspot of aircraft structural fault research because of its good performance. Facing the difficulties of structural fault location of traditional spacecraft, slow data updating speed and poor transplant ability of positioning device, a structural fault angle measurement model based on FBG strain flower is constructed by combining FBG sensor with the principle of right-angle strain flower. On the problem of determining the main strain orientation, two groups of FBG strain rosette locations are selected to determine, and different groups of locations are cross-solved to obtain the original coordinates of impact. At the same time, aiming at the structural problems of four simple thin plates in the aircraft, a method of judging the structural load based on the disturbance trend is proposed. In the process of experiment, it is necessary to test the positioning accuracy of the structure obtained by the sensor and the size error of the load. In order to better simulate the real scene, a simulation platform of aircraft structure impact is built. During the testing process, it is found that the sensor detection platform proposed in this study can locate structural faults within 2.8 cm. The average time required for location judgment is about 1.7 ms, and the error of structural impact force is about 2.86 N. Through this study, a new detection method for structural fault detection of spacecraft is proposed, which can better ensure the safety of spacecraft.

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