Fiber Bragg Grating Sensors Research Articles

High-Resolution and Extended-Range Fiber Bragg Grating Sensing System Based on a Microwave Photonic Filter with Period-breaking Interrogation Method

High-Resolution and Extended-Range Fiber Bragg Grating Sensing System Based on a Microwave Photonic Filter with Period-breaking Interrogation Method

Long-Distance Quasi-Distributed FBG Sensor System Based on Time-Division Multiplexing

Long-Distance Quasi-Distributed FBG Sensor System Based on Time-Division Multiplexing

Rapid and efficient identification of Cd (II) ions in water with functionalized gold nano particle coated etched FBG Sensors

Rapid and efficient identification of Cd (II) ions in water with functionalized gold nano particle coated etched FBG Sensors

Enhancing Consumer Electronics in Healthcare 4.0: Integrating Passive FBG Sensor and IoMT Technology for Remote HRV Monitoring

Enhancing Consumer Electronics in Healthcare 4.0: Integrating Passive FBG Sensor and IoMT Technology for Remote HRV Monitoring

An FBG Sensor Placement Method to Achieve Long Fatigue Life and High Measurement Accuracy in Deformation Sensing of Satellite Solar Panels

An FBG Sensor Placement Method to Achieve Long Fatigue Life and High Measurement Accuracy in Deformation Sensing of Satellite Solar Panels

Evaluation of Concrete Carbonation Based on a Fiber Bragg Grating Sensor.

The carbonation of concrete greatly affects its service life. In this paper, fiber Bragg grating (FBG) sensors were used to investigate the relationship between concrete carbonation and its mechanical properties. A T130 High Sensitivity Strain Cable Sensor with a good linearity was used to monitor the internal strain in concrete, to investigate the variation in the elastic modulus of concrete with carbonation time. A mathematical model of elastic modulus and carbonation time of concrete based on FBG was established. At the same time, the authors explored the relationship between the carbonation depth and compressive strength of concrete and the carbonation time using a phenolphthalein solution test and a compressive strength test, respectively. The experimental results indicate that the carbonation depth, compressive strength, and elastic modulus of concrete increase with carbonation time. In the early stage of carbonation, these three parameters increase rapidly, while they grow slowly in the later stage of carbonation. The varying trend of the elastic modulus of concrete is consistent with the compressive strength, which shows a binomial relationship. Therefore, the elastic modulus, measured using FBG sensors, is used as an indicator of the characterization of the carbonation resistance of concrete. This work provides a new approach for concrete carbonation detection and assessment.

Design of Graphene Coated on FBG for High Temperature Sensor

This article reported design of FBG Sensor layered by 2D Graphene Material. In this research, the FBG was coated with single layer graphene material, then the outher FBG has been coated with Aluminium, Chromium Oxide, PMMA, and Silica. The finite element method was used to analyze the profile of each coated-FBG with a thickness of 20 µm. Furthermore, the sensitivity of each designed coated-FBGs for the temperature measurement was calculated in the range of 25 oC – 300 oC. Design and analysis of coated FBG found that the FBG coated with graphene then layered by PMMA material has the highest sensitivity of 406.4 pm/℃. Although the sensitivity was 395.73pm/℃ for PMMA material. It was followed by Aluminium coating material which yields the sensitivity of 71.367pm/℃. The Silica and Chromium oxide yield the same sensitivity of 13.73pm/℃. Furthermore, the simulation results shows that the design of coated FBGs with a Gaussian apodization has the narrowest FWHM width of 1.3 nm. While the Tanh and Uniform apodization yield FWHM width of 3.724 nm and 3.732 nm respectively. Certainly, the best FBG design for high temperature sensor was proposed by FBGs coated by graphene and layered with PMMA material with Gaussian apodization

A highly sensitive diaphragm pressure sensor based on fiber Bragg grating with multiprobe configuration

The demand for accurate low-pressure sensing has become indispensable across diverse industries and research domains, where meticulous pressure monitoring holds paramount significance. This research work presents the development of a multiprobe extrinsically sensitive low pressure fiber Bragg grating (FBG) sensor. Three distinct diaphragm-based FBG sensing probes, equipped with silicone diaphragms of 0.5 mm, 1 mm, and 2 mm thickness, are developed within a unified assembly. This design offers the flexibility to select a probe based on the pressure magnitude and desired sensitivity and resolution. The displacement of diaphragm centers within the probes, caused by pressure variations in gas pipe channels, is actuated through an FBG-cantilever system. The sensor exhibits a dynamic range spanning 0 to 10 psi, featuring a peak sensitivity of 1.635 nm/psi. With a negligible hysteresis of 0.2 % observed in a complete operational cycle, the sensor demonstrates consistent stability across various constant pressure conditions, characterized by an average transient of <1 %. Furthermore, cyclic testing reveals an average deviation of 1.58 % in sensor response. This innovative sensor offers promising avenues for industrial applications and research and development endeavors that necessitate precise and reliable pressure measurements in the low pressure domains.

High-precision FBG-based sensor for soil settlement monitoring: A comparative study with magnetic settlement gauges and PIV technique

The primary objective of layered settlement monitoring is to detect subsidence issues in soil or foundational structures, in order to implement appropriate measures for ensuring the safety and stability of engineering projects. Conventional monitoring techniques have problems such as errors in manual readings, high costs, susceptibility to interference, and low levels of automation. A layered soil settlement sensor based on fiber Bragg grating (FBG) technology is proposed in this study. This sensor utilizes an equal-strength beam as an "intermediate bridge" to make the FBG sensor respond. The sensor is prepared by the laboratory's 3D fused deposition modelling (FDM) and calibrated by applying displacement loads through a fine-tuning platform. The sensitivity coefficient is 0.068 nm/mm, and the correlation coefficient exceeds 0.99. Finally, the sensor exhibited high precision when compared to measurements obtained from magnetic settlement gauges and particle image velocimetry (PIV). The discrepancies between the measurement outcomes of the sensor and the actual values of soil settlement does not exceed 3.33%.

Vibration Suppression of a Flexible Beam Structure Coupled with Liquid Sloshing via ADP Control Based on FBG Strain Measurement

In this study, an adaptive dynamic programming (ADP) control strategy based on the strain measurement of a fiber Bragg grating (FGB) sensor array is proposed for the vibration suppression of a complicated flexible-sloshing coupled system, which usually exists in aerospace engineering, such as launch vehicles with a large amount of liquid propellant as well as a flexible beam structure. To simplify the flexible-sloshing coupled dynamics model, the equivalent spring-mass-damper (SMD) model of liquid sloshing is employed, and a finite-element method (FEM) dynamic model for the beam structure coupled with the liquid sloshing is mathematically established. Then, a strain-based vibration dynamic model is derived by employing a transformation matrix based on the relationship between displacement and strain of the beam structure. To facilitate the design of a strain-based control, a tracking differentiator is designed to provide the strains’ derivative signals as partial states’ estimations. Feeding the system with the strain measurements and their derivatives’ estimations, an ADP controller with an action-dependent heuristic dynamic programming structure is proposed to suppress the vibration of the flexible-sloshing coupled system, and the corresponding Lyapunov stability of the closed-loop system is theoretically guaranteed. Numerical results show the proposed method can effectively suppress coupled vibration depending on limited strain measurements irrespective of external disturbances.

Blast wave induced strain measurements in polymers using FBG sensor inside shock tube

Polypropylene and polytetrafluoroethylene (Teflon) have several applications in the aerospace industry and the study of their behaviour in high speed impact events is of great significance. This paper demonstrates the use of FBG sensors for measuring blast wave induced strain in aerospace grade polymer samples inside a Vertical Shock Tube (VST). FBG strain measurement assembly incorporating the polymer test sample and embedded FBG sensor has been designed and developed for suitably mounting it in the driven section of the VST. Experiments are carried out by impacting the polymer samples with blast waves of different peak pressures generated inside VST. PCB pressure transducer is used to record the blast pressure profile in the VST. A systematic study of strain profiles developed in the polymer test samples and their dependence on incident blast wave parameters has been carried out. The strain profiles measured by FBG in both the polymer samples are analysed using FFT and continuous wavelet transform analyses. FEM analysis is carried out using ABAQUS dynamic explicit to simulate the blast wave induced compression in polymers for different blast wave peak pressures and compared with experimental results. The application of FBG sensors to measure blast wave induced dynamic strain inside polymer materials and their capability to withstand the harsh environment of impulse test facilities like shock tubes has been demonstrated.

Temperature-Insensitive Fiber Bragg Grating Sensing System for Curvature Measurement Based on Optoelectronic Oscillator With the Enhanced Vernier Effect

Temperature-Insensitive Fiber Bragg Grating Sensing System for Curvature Measurement Based on Optoelectronic Oscillator With the Enhanced Vernier Effect

Meta-Learning for Boosting the Sensing Quality and Utility of FSO-Based Multichannel FBG Sensor System

Meta-Learning for Boosting the Sensing Quality and Utility of FSO-Based Multichannel FBG Sensor System

Extension of Fiber Bragg Grating Ultrasound Sensor Network by Adhesive Couplers

Previous studies demonstrated coupling of acoustic guided waves from one optical fiber to another through a simple adhesive bond coupler. This paper experimentally utilizes such an adhesive bond coupler to easily extend an already existing sensor network. We experimentally demonstrate this concept for detecting simulated cracks growing from circular holes in a thin aluminum plate. A single, remotely bonded FBG sensor is used to detect the original crack growth, followed by the addition of other optical fiber segments using adhesive couplers to detect new crack growth locations on the plate. A laser Doppler vibrometer is also used to measure the guided wave propagation through the plate to verify that the changes in the FBG sensor measurements are due to the growth of the cracks.

CFRP drive shaft damage identification and localization based on FBG sensing network and GWO-BP neural networks

Carbon Fiber Reinforced Plastic (CFRP) has the advantages of light weight, high strength, small coefficient of thermal expansion, good vibration damping performance, etc., the use of its production drive shaft can reduce weight, improve the intrinsic frequency, transmission efficiency and precision, and has been used in helicopters, heavy duty machine tools, wind turbines, ships and other high-end equipment. Once the damage occurs, it will cause adverse effects such as reduction of mechanical efficiency of the system, degradation of transmission system performance, and decrease of reliability and safety. The existing non-destructive testing technology for carbon fiber reinforced plastic has limitations such as inconvenient use, complex equipment, and no real-time online monitoring. To address this problem, this paper adopts Fiber Bragg Gratings (FBG) sensors to obtain real-time strain field data of CFRP drive shaft, and uses the linear and nonlinear mapping ability of Back Propagation Neural Network (BP neural network) to identify and locate the damage of CFRP drive shaft. At the same time, the GWO optimization algorithm is used to optimize the BP neural network to construct a CFRP drive shaft damage identification and localization system based on FBG sensing network and GWO-BP neural network. The experiments show that the CFRP drive shaft damage identification and localization system constructed in this paper can obtain the CFRP drive shaft strain field information in real time and accurately identify the damage and its location.

Strain transfer of fiber Bragg grating sensors in fiber-reinforced polymer composites with different fiber orientations and temperatures

A comprehensive investigation integrating a newly developed strain transfer model and corresponding experiments has been performed, so as to characterize and quantify the fiber Bragg grating (FBG) sensor’s strain transfer mechanisms and measurement accuracy in composite structures considering fiber orientations and temperatures. Tensile tests at different temperatures (20 ℃, 40 ℃, 80 ℃, and 100 ℃) were performed on the related specimens. The results show that the geometry and temperatures affect the measurement accuracy significantly, and with the strain modification based on the developed model, the accuracy has been substantially improved. The maximum error decreases from 9.3 % to 1.4 % at room temperature and is about 4.1 % at high temperatures. The sensitivity analysis illustrates that the embedding length is the most critical factor affecting the accuracy, followed by the polymer’s shear modulus and the coating layer radius. The strain transfer efficiency has a minor sensitivity to temperature and interface parameters.

Detection of Low Hydrostatic Pressure Using Fiber Bragg Grating Sensor

Detection of Low Hydrostatic Pressure Using Fiber Bragg Grating Sensor

Monitoring experiment and simulation on solidification of DNAN based melt‐cast explosive with FBG sensors

AbstractIn order to obtain the change rule of the temperature field and the mechanism of defect formation during the solidification process of melt‐cast explosive, the temperature field change data were tested during the solidification process of DNAN based melt‐cast explosive by using an arrayed spatially distributed Fiber Bragg Grating (FBG) temperature sensor device. The temperature field variation during the solidification experiment was obtained under the condition that the cooling rate of the boundary water‐bath temperature was 0.2 °C/min. On the basis of the solidification experiments, the macroscopic solidification process of small‐caliber grenade at different boundary cooling rates was simulated using ProCAST software. The simulation results show that when the boundary cooling rate is 0.2 °C/min, the temperature fields during the solidification process of DNAN based melt‐cast explosive are in good agreement with that of the experimental monitoring points; the size of the melt‐cast charge defects decreases as the boundary cooling rate becomes smaller; and the location of the charge defects is closer to the tail of the grenade as the cooling rate decreases. In addition, a mesoscopic model of DNAN based melt‐cast explosive was established in the paper. At the mesoscopic level, the generation, formation, and evolution of charge defects in DNAN based melt‐cast explosive during solidification were investigated. The study results provide theoretical guidance for the formulation design and process optimization of DNAN based melt‐cast explosives, as well as for improving the charge quality of ammunition.

A New Interrogation System for FBG Sensors based on Midband Filter with Correction

In this paper, a midband interrogation system for Fiber Bragg Grating (FBG) sensors is presented and its numerical demonstration is reported. The midband interrogation system is based on a finite reflection filter with automatic correction. The filter is used to interrogate the FBG sensors. The strain FBG sensors were used to demonstrate the effectiveness of the proposed systems. The results demonstrate that the proposed system of interrogation has a great resolution (±1 pm) with good stability.

Monitoring Surface State of AA7075-T6 during Dynamic Loading with FBG Sensor

Monitoring Surface State of AA7075-T6 during Dynamic Loading with FBG Sensor