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.

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.

scholarly journals Cladding Modified Fiber Bragg Grating for Copper Ions Detection

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Husam Abduldaem Mohammed ◽  
Aqiel Almamori ◽  
Ali A. Alwahib
Keyword(s):  
Fiber Bragg Grating ◽  
Copper Ions ◽  
Evanescent Field ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Chemical Agent ◽  
Toxic Heavy Metal ◽  
Fbg Sensor ◽  
Fbg Sensors ◽  
Significant Wavelength

This paper reports a fiber Bragg grating (FBG) as a biosensor. The FBGs were etched using a chemical agent,namely,hydrofluoric acid (HF). This implies the removal of some part of the cladding layer. Consequently, the evanescent field propagating out of the core will be closer to the environment and become more sensitive to the change in the surrounding. The proposed FBG sensor was utilized to detect toxic heavy metal ions aqueous medium namely, copper ions (Cu2+). Two FBG sensors were etched with 20 and 40 μm diameters and fabricated. The sensors were studied towards Cu2+ with different concentrations using wavelength shift as a result of the interaction between the evanescent field and copper ions. The FBG sensors showed a good response in terms of significant wavelength shift in corresponding to varying Cu2+ concentrations when immersed in aqueous mediums. The sensors exhibited excellent repeatability towards Cu ions.The results demonstrate that the smaller FBG etching diameter, the better optical response in terms of wavelength and linearity. 

scholarly journals Real Time Monitoring of Railway Traffic Using Fiber Bragg Grating Sensors

2010 ◽  
Author(s):  
M. L. Filograno ◽  
A. Rodri´guez-Barrios ◽  
M. Gonza´lez-Herraez ◽  
P. Corredera ◽  
S. Marti´n-Lo´pez ◽  
...  
Keyword(s):  
Fiber Bragg Grating ◽  
High Speed ◽  
Field Tests ◽  
Bragg Grating ◽  
Railway Traffic ◽  
Fbg Sensor ◽  
Commercial Operation ◽  
Load Calculation ◽  
Different Types ◽  
Fbg Sensors

In this work we present field tests concerning the application of Fiber Bragg Grating (FBG) sensors for the monitoring of railway traffic. The test campaigns are performed on the Spanish high speed line Madrid–Barcelona, with different types of trains (S-102 TALGO–BOMBARDIER, S-103 SIEMENS-VELARO and S-120 CAF). We located the FBG sensors in the rail track at 70 km from Madrid in the country side, where the trains primarily are tested during commercial operation with maximum speeds between 250–300 km/h. The FBG sensor interrogation system used allows the simultaneous monitoring of four FBG sensors at 8000 samples/s. The different position of the FBG sensors in relation with the rail can be used with different purposes such as train identification, axle counting, speed and acceleration detection, wheel imperfections monitoring and dynamic load calculation.

scholarly journals Design Reliable Bus Structure Distributed Fiber Bragg Grating Sensor Network Using Gated Recurrent Unit Network

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7355
Author(s):  
Amare Mulatie Dehnaw ◽  
Yibeltal Chanie Manie ◽  
Ya Yu Chen ◽  
Po Han Chiu ◽  
Hung Wei Huang ◽  
...  
Keyword(s):  
Sensor Networks ◽  
Fiber Bragg Grating ◽  
Wavelength Division Multiplexing ◽  
Bragg Grating ◽  
Bragg Wavelength ◽  
Wavelength Division ◽  
Fbg Sensor ◽  
Bus Structure ◽  
Fbg Sensors ◽  
Gated Recurrent Unit

The focus of this paper was designing and demonstrating bus structure FBG sensor networks using intensity wavelength division multiplexing (IWDM) techniques and a gated recurrent unit (GRU) algorithm to increase the capability of multiplexing and the ability to detect Bragg wavelengths with greater accuracy. Several Fiber Bragg grating (FBG) sensors are coupled with power ratios of 90:10 and 80:10, respectively in the suggested experimental setup. We used the latest IWDM multiplexing technique for the proposed scheme, as the IWDM system increases the number of sensors and allows us to alleviate the limited operational region drawback of conventional wavelength division multiplexing (WDM). However, IWDM has a crosstalk problem that causes high-sensor signal measurement errors. Thus, we proposed the GRU model to overcome this crosstalk or overlapping problem by converting the spectral detection problem into a regression problem and considered the sequence of spectral features as input. By feeding this sequential spectrum dataset into the GRU model, we trained the GRU system until we achieved optimal efficiency. Consequently, the well-trained GRU model quickly and accurately identifies the Bragg wavelength of each FBG from the overlapping spectra. The Bragg wavelength detection performance of our proposed GRU model is tested or validated using different numbers of FBG sensors, such as 3-FBG, 5-FBG, 7-FBG, and 10-FBG, separately. As a result, the experiment result proves that the well-trained GRU model accurately identifies each FBG Bragg wavelength, and even the number of FBG sensors increase, as well as the spectra of FBGs, which are partially or fully overlapped. Therefore, to boost the detection efficiency, reliability, and to increase the multiplexing capabilities of FBG sensor networks, the proposed sensor system is better than the other previously proposed methods.

scholarly journals Development of Sandglass Shape FBG Sensor to Reduce Cross Sensitivity Effect

2013 ◽  
Vol 2013 ◽  
pp. 1-3 ◽  
Author(s):  
Bo Zhang
Keyword(s):  
Temperature Measurement ◽  
Fiber Bragg Grating ◽  
Pressure Sensor ◽  
Pressure Measurement ◽  
Axial Strain ◽  
Bragg Grating ◽  
Cross Sensitivity ◽  
Fbg Sensor ◽  
Transverse Pressure ◽  
Fbg Sensors

Fiber Bragg grating (FBG) sensors have received considerable attention in applications of temperature, axial strain, and transverse pressure measurement. However, the cross-sensitivity of strain and temperature measurement is the key problem of FBG sensors. In this paper, a sandglass shape FBG is proposed to divide cross-sensitivity of temperature and transverse pressure. The principle and structure of sandglass FBG are introduced, and the experiment results show cross-sensitivity avoidable in the transverse pressure sensor.

scholarly journals Demonstration of a Filterless, Multi-Point, and Temperature-Independent Fiber Bragg Grating Dynamical Demodulator Using Pulse-Width Modulation

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5825
Author(s):  
Joao B. Rosolem ◽  
Marcio C. Argentato ◽  
Fábio R. Bassan ◽  
Rivael S. Penze ◽  
Claudio Floridia ◽  
...  
Keyword(s):  
Fiber Bragg Grating ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Optical Filter ◽  
Tunable Laser ◽  
Harsh Environments ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Fbg Sensor ◽  
Fbg Sensors

We demonstrated in this work a filterless, multi-point and temperature-independent FBG (fiber Bragg grating) dynamical demodulator using pulse-width-modulation (PWM). In this approach, the FBG interrogation system is composed of a tunable laser and a demodulator that is designed to detect the wavelength shift of the FBG sensor without any optical filter making it very suitable to be used in harsh environments. In this work, we applied the proposed method that uses the PWM technique for FBG sensors placed in high pressure and high-temperature environments. The proposed method was characterized in the laboratory using an FBG sensor modulated in a frequency of 6 Hz, with a 1 kHz sweeping frequency in the wavelength range from 1527 to 1534 nm. Also, the method was evaluated in a field test in an engine of a thermoelectric power plant.

scholarly journals Application of the Microclamped Fiber Bragg Grating (FBG) Sensor in Rock Bolt Support Quality Monitoring

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Xinxin Guo ◽  
Bo Wang ◽  
Zhenyu Wang ◽  
Wei Yu ◽  
Zhenwang Ma ◽  
...  
Keyword(s):  
Fiber Bragg Grating ◽  
Mechanical Performance ◽  
Rock Bolt ◽  
Theoretical Formula ◽  
Bragg Grating ◽  
Test Sensitivity ◽  
Fbg Sensor ◽  
Measured Strain ◽  
Fbg Sensors ◽  
Rock Bolt Support

The force-measuring rock bolt instrumented with bare fiber Bragg grating (FBG) sensors are generally factory-fabricated. To enable users to fabricate a force-measuring rock bolt by themselves, the microclamped FBG sensor is proposed to replace the encapsulated bare FBG sensor. A theoretical formula of strain sensitivity is also established. The strain sensibility measured by indoor calibration is consistent with the theoretical one, indicating that the microclamped FBG sensor can measure strain accurately. Besides, the measured strain sensibility coefficient (wavelength difference/strain) matches the theoretical values, making the installed microclamped sensor free from the need for recalibration and proving the installation method to be reliable. Also, the test sensitivity can be adjusted as needed. The instrumented rock bolt with microclamped FBG sensors shows great mechanical performance in the field test, awaiting further usage in applications.

Vibration Fatigue Test Based on Fiber Bragg Grating Sensors and HHT

2013 ◽  
Vol 328 ◽  
pp. 193-197
Author(s):  
Si Jin Xin ◽  
Zhen Tong
Keyword(s):  
Titanium Alloy ◽  
Fiber Bragg Grating ◽  
Fatigue Test ◽  
Alloy Sheet ◽  
Bragg Grating ◽  
Metal Fatigue ◽  
Hilbert Huang Transform ◽  
Time Frequency ◽  
Vibration Fatigue ◽  
Fbg Sensors

The metal fatigue is an important factor to cause an accident in machine operation, so metal fatigue test is a significant procedure in manufacturing. Fiber Bragg Grating (FBG), as an innovative sensor, has been applied to the measurement of various rotating machines. In this paper, the time-frequency analysis is used to detect the fatigue feature of a titanium alloy measured by FBG sensors. Furthermore, the Hilbert-Huang transform (HHT) is more effective to observe the fatigue limit of the titanium alloy sheet, compared to the Wavelet transform (WT).

Measurement of the Thermal Expansion for Space Structures Using Fiber Bragg Grating Sensors and Displacement Measuring Interferometers

2008 ◽  
Author(s):  
Hong-Il Kim ◽  
Lae-Hyong Kang ◽  
Jae-Hung Han
Keyword(s):  
Fiber Bragg Grating ◽  
Real Time ◽  
Deformation Monitoring ◽  
Space Environment ◽  
Space Structures ◽  
Bragg Grating ◽  
Environment Change ◽  
Time Deformation ◽  
Fiber Bragg Grating Sensors ◽  
Fbg Sensors

Dimensional stability of the space structures, such as large telescope mirrors or metering substructures, is very important because even extremely small deformations of these structures might degrade the optical performances. Therefore, precise deformation data of the space structures according to environment change are required to design these structures correctly. Also, real-time deformation monitoring of these structures in space environment is demanded to verify whether these structures are properly designed or manufactured. FBG (fiber Bragg grating) sensors are applicable to real time monitoring of the space structure because they can be embedded onto the structures with minimal weight penalty. In this research, therefore, thermal deformation measurement system for the space structures, composed of FBG sensors for real time strain measurement and DMI (displacement measuring interferometers) for accurate specimen expansion data acquisition, is developed. Thermal strains measured by distributed FBG sensors are evaluated by the comparison with the strains obtained by highly accurate DMI.

scholarly journals Femtosecond-Laser-Assisted Fabrication of Radiation-Resistant Fiber Bragg Grating Sensors

2022 ◽  
Vol 12 (2) ◽  
pp. 886
Author(s):  
Hun-Kook Choi ◽  
Young-Jun Jung ◽  
Bong-Ahn Yu ◽  
Jae-Hee Sung ◽  
Ik-Bu Sohn ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Fiber Bragg Grating ◽  
Optical Fibers ◽  
Coming Out ◽  
Single Mode ◽  
Femtosecond Laser Irradiation ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Radiation Resistant ◽  
Fbg Sensors

This paper demonstrates the fabrication of radiation-resistant fiber Bragg grating (FBG) sensors using infrared femtosecond laser irradiation. FBG sensors were written inside acrylate-coated fluorine-doped single-mode specialty optical fibers. We detected the Bragg resonance at 1542 nm. By controlling the irradiation conditions, we improved the signal strength coming out from the FBG sensors. A significant reduction in the Bragg wavelength shift was detected in the fabricated FBG sensors for a radiation dose up to 105 gray, indicating excellent radiation resistance capabilities. We also characterized the temperature sensitivity of the radiation-resistant FBG sensors and detected outstanding performance.

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