Fiber Bragg Grating Acceleration Sensor Research Articles

A novel fiber Bragg grating acceleration sensor based on the double-hinge structure

A novel fiber Bragg grating acceleration sensor based on the double-hinge structure

Fiber bragg grating accelerometer based on asymmetric shaped flexible hinge structure

To achieve real-time health monitoring in civil engineering, a FBG acceleration sensor with asymmetric shaped flexible hinge structure is proposed. Combined with the theoretical analysis, the expressions of resonance frequency and sensitivity are deduced, and the effects of the structural parameters of the sensor on the resonance frequency and sensitivity are analyzed and simulated. Based on the optimization results, a fiber Bragg grating acceleration sensor was designed and fabricated. The amplitude-frequency response, linear sensitivity response, and lateral anti-interference ability were tested experimentally. The experimental data shows a sensor resonance frequency of 350 Hz, a sensitivity of 90.96 pm/g, and a linear correlation of 99.59%. These results closely align with the theoretical predictions of a resonance frequency of 344 Hz, and a sensitivity of 98 pm/g, confirming the accuracy of the sensor's theoretical analysis.The transverse interference immunity of the sensor is 3.7%, and an operating frequency band of 10–250 Hz. It indicates that the sensor is promising for medium and low frequency vibration measurement.

Research on S-type fiber Bragg grating acceleration sensor for low-frequency vibration monitoring.

The acquisition of low-frequency vibration signals in earthquake exploration is a crucial aspect of seismic exploration technology. Addressing the difficulty current fiber optic sensors face in monitoring low-frequency vibrations, this paper proposes an acceleration sensor based on S-type Fiber Bragg Grating (FBG). First, an FBG acceleration sensor model is established and theoretically analyzed. Then, the impact of structural parameters on the sensor's sensitivity and natural frequency is examined, employing the ANSYS finite element analysis software for static stress and modal simulation analysis. Finally, a prototype is developed, and a low-frequency vibration testing system is assembled to test the sensor's performance. The results show that the sensor has a natural frequency of 34Hz, operates in a frequency band of 0.2-14Hz, has a dynamic range of 63.5 dB, a lateral interference of less than 3%, a sensitivity of ∼274.45 pm/g, good linearity, and is insensitive to temperature. The findings provide a reference for the development of similar sensors and further exploration of the lower frequency limit.

A Low-Frequency Fiber Bragg Grating Acceleration Sensor Based on Spring Support and Symmetric Compensation Structure with Flexible Hinges.

To measure vibration signals, a low-frequency fiber Bragg grating (FBG) acceleration sensor featuring a flexible hinge with a spring support and symmetric compensation structure has been designed. Based on the mechanical model of the sensor's structure, the expressions for sensitivity and resonant frequency of the sensor are derived. The structural parameters of the sensor are optimized, and a simulation analysis is conducted using ANSYS 19.2 software. According to the results of simulation analysis and size optimization, the sensor prototype is constructed. Subsequently, its amplitude-frequency response, sensitivity, and temperature characteristics are investigated through vibration experiments. The experimental results show that the resonant frequency of the sensor is 73 Hz, the operating frequency range is 0~60 Hz, and the sensitivity measures 24.24 pm/g. This design meets the requirements for measuring vibration signals at low frequencies.

Miniaturized fiber Bragg grating accelerator sensors for low-frequency vibration monitoring.

Acceleration monitoring is an important technical means of seismic monitoring, oil exploration, deep well observation, etc. A miniaturized fiber Bragg grating (FBG) acceleration sensor with three cantilever beams is proposed against the fact that it is difficult for fiber-optic sensors to meet the requirements for low-frequency vibration monitoring. First, the model of the FBG acceleration sensor was built and theoretically analyzed; second, the effect of structural parameters on sensor sensitivity and natural frequency was analyzed, and the sensors were subjected to static stress analysis and modal simulation analysis through the ANSYS finite element analysis software; finally, the real sensors were developed and subjected to performance tests with a low-frequency vibration test system. According to the result, the natural frequency of the sensor is about 64Hz, and its sensitivity is 201.3pm/g; favorable linearity is observed at the working frequency band of 0.1-40Hz, and the transverse interference is less than 2.51%. The research findings offer a reference for the development of like sensors and the further exploration of the lower limit of low frequency.

A fiber Bragg grating acceleration sensor based on a circular flexure hinge structure for medium- and high-frequency vibration measurements

A fiber Bragg grating acceleration sensor based on a circular flexure hinge structure for medium- and high-frequency vibration measurements

A 2-D Fiber Bragg Grating Acceleration Sensor Based on Circular Flexure Hinges Structure

This work proposes and experimentally validates a 2D low- and medium-frequency fiber Bragg grating (FBG) acceleration sensor. The investigation of the vibration sensor uses a symmetrical circular flexure hinge structure with similar sensitivity in both measuring directions. The two FBGs are arranged differently to avoid a temperature impact; the sensitivity is double that of only one FBG fiber. First, the operating theory and theoretical system of the FBG accelerometer were analyzed. Second, the theoretical research and optimization improved the FBG sensor’s design, resonance frequency, and sensitivity. Third, the viability of the optimization findings and the simulation was evaluated using ANSYS software. Finally, the product was created, and the sensor calibration was performed using the simulation results. The theoretical values and experimental findings largely concur. According to performance tests, the resonance frequencies in the x- and y-direction are 440 and 500 Hz, respectively, with a flat frequency range from 20 to 300 Hz. Furthermore, the sensor shows average sensitivities along the two spatial dimensions of 124 and 83 pm/G, respectively. The overall anti-interference between the two measuring directions is less than 6%. This sensor is useful in various applications, including vibration monitoring, machine condition monitoring, and robotics.

Fiber Bragg Grating Acceleration Sensor Based on Circular Cycloid Hinge

Fiber Bragg Grating Acceleration Sensor Based on Circular Cycloid Hinge

Medium and low frequency fiber Bragg grating acceleration sensor based on single-sided single-arc hinge

A medium and low frequency fiber Bragg grating (FBG) based acceleration sensor based on single-axis single-arc hinge-shaped sensitization structure is designed and experimentally demonstrated. The theoretical formula of the sensor's resonance frequency and sensitivity was given, the stress distribution, characteristic frequency and amplitude frequency characteristics of the sensor were simulated and the structural parameters of the sensor were optimized. The experimental results show that the resonance frequency of the sensor is 630 Hz, the flat frequency range is 30–300 Hz, and the acceleration sensitivity is 57.77 pm/g. The sensor has the advantages of high sensitivity, wide flat frequency range and strong transverse anti-interference ability, which can meet the requirements of acceleration detection in petroleum exploration field.

Design and test of a low frequency Fiber Bragg Grating acceleration sensor with double tilted cantilevers

The collection of low-frequency vibration signals is very important for the monitoring research in various fields such as national defense engineering, bridges and dams, aerospace, and the earthquake resistance of civil building structures. During the structural design of existing cantilever Fiber Bragg Grating (FBG) acceleration sensors, the tilt angle of the cantilever is often ignored, therefore, aiming at this problem, this paper proposed a new FBG acceleration sensor with double titled cantilevers, and used formula derivation and ANSYS software to optimize the structural parameters of the proposed sensor and conduct simulation analysis. Then, according to the simulation results, two sensor prototypes were fabricated, one with tilted cantilevers and the other with horizontal cantilevers, then, the performance of the two was tested, compared, and analyzed to verify the impact of the tilt angle of cantilevers on the performance of the sensor. The experimental results showed that, the natural frequency of the proposed sensor was about 46 Hz, which can be used to monitor vibration signals with the 6–30 Hz frequency range; the sensitivity of the proposed sensor was about 4.16 pm/m s−2; and its degree of lateral an-interference was less than 5.62%. Compared with the sensor with horizontal cantilevers, the flat response area of the sensor with tilted cantilevers increased by about 30%, while its sensitivity reduced by about half. The research findings of this paper provide a useful reference for the research on similar type sensors and further expansion of the measurement range of FBG acceleration sensors.

A Fiber Bragg Grating acceleration sensor with temperature compensation

A Fiber Bragg Grating(FBG) accelerometer based on a composite beam is proposed. Owing to the opposite movement of the two FBGs, the influence of temperature can be reduced and the sensitivity can be improved by the difference operation of FBGs’ center wavelength shift. Through theoretical analysis and simulation of the proposed sensor, the sensor structure parameters are determined. The theory of the proposed sensor is verified by experiments, and the experimental results show that the temperature impact on the sensor structure is reduced to 0.47 pm/℃ in the range of 25–75 ℃. The accelerometer has a good response flat region at 40–140 Hz and the sensitivity is 234.5 pm/g. The orthogonal crosstalk of the accelerometer is −21.01 dB. The proposed FBG acceleration sensor has a good application prospect in low-frequency oil and gas seismic exploration.

A High-Frequency Acceleration Sensor Based on Fiber Grating

Fiber Bragg grating (FBG) acceleration sensor is an important branch of FBG application and has irreplaceable advantages compared with an electronic accelerometer. An FBG acceleration sensor with high sensitivity and high natural frequency is designed. This sensor adopts a double cantilever structure to sense the vibration perpendicular to the axis. Compared with a single cantilever structure, the natural frequency is increased without reducing the sensing length. Through the above structure design and material selection, the sensor shows a high natural frequency of 8658 Hz and its sensitivity is 0.44 pm/g. After the photoelectric demodulation is used, the sensitivity is 52 mV/g and the linearity is 0.998. Through the experiment and simulation analysis, the sensor performs good anti-interference in the transverse direction and temperature compensation in the process of vibration measurement. The system is very small due to the use of light intensity demodulation technology, which is conducive to application and integration in actual measurement scenarios.

Fiber Bragg grating accelerometer-based nonintrusive flow rate measurements and leak detection.

We aim to develop a nonintrusive, reliable, convenient flow rate measurement and leak detection method. The flow rate is known to be related to the vibration excited by the turbulent internal flow, but there exists some scatter in the vibration data at low flow speeds (<2m/s) due to the resolution limits of the sensor. A customized fiber Bragg grating acceleration sensor is designed and applied to measure the low flow rate and detect leakage in the pipeline. Experimental tests show the relationship between the standard deviation of vibration data and flow rate at low velocity is quadratic; the R2 of quadratic curve fitting is 0.990. Moreover, for leak detection, selected features are used as the input of support vector machine classifiers to identify the leak in the pipeline. The results demonstrate that the proposed method achieves a high accuracy of 99.00% to determine the leak state and nonleak state.

High Sensitivity Fiber Bragg Grating Acceleration Sensor Based on Rigid Hinge

In order to break through low sensitivity limitation of the existing fiber Bragg grating (FBG) acceleration sensor, a new high sensitivity FBG acceleration sensor based on rigid hinge is proposed. The working principle innovation is that the sensor uses the rigid body rotation motion instead of the existing elastic deformation. The novel structure is that the pendulum rotates around the rigid hinge and the structure is symmetrically designed, which increases the elongation of the fiber grating by twice. The resonance frequency and sensitivity formula of FBG acceleration sensor is theoretically obtained by analysis. The influence of size parameters of the structure on sensor sensitivity and resonance frequency is further analyzed by MATLAB, and finally the structural parameters are optimized. On the basis, the first-order natural frequency of the sensor is simulated by ANSYS Workbench17.0. Experimental studies show that the natural frequency of the acceleration sensor designed in this paper is 39 Hz, the sensitivity of the sensor is 949.2 pm/g at 15 Hz, and the cross-interference is less than 6.49%, which is suitable for precision measurement under low frequency micro-vibration.

Diaphragm Based Fiber Bragg Grating Acceleration Sensor with Temperature Compensation.

A novel fiber Bragg grating (FBG) sensing-based acceleration sensor has been proposed to simultaneously decouple and measure temperature and acceleration in real-time. This design applied a diaphragm structure and utilized the axial property of a tightly suspended optical fiber, enabling improvement in its sensitivity and resonant frequency and achieve a low cross-sensitivity. The theoretical vibrational model of the sensor has been built, and its design parameters and sensing properties have been analyzed through the numerical analysis. A decoupling method has been presented with consideration of the thermal expansion of the sensor structure to realize temperature compensation. Experimental results show that the temperature sensitivity is 8.66 pm/°C within the range of 30–90 °C. The acceleration sensitivity is 20.189 pm/g with a linearity of 0.764% within the range of 5~65 m/s2. The corresponding working bandwidth is 10~200 Hz and its resonant frequency is 600 Hz. This sensor possesses an excellent impact resistance for the cross direction, and the cross-axis sensitivity is below 3.31%. This implementation can avoid the FBG-pasting procedure and overcome its associated shortcomings. The performance of the proposed acceleration sensor can be easily adjusted by modifying their corresponding physical parameters to satisfy requirements from different vibration measurements.

A novel fiber Bragg grating acceleration sensor for measurement of vibration

A novel fiber Bragg grating (FBG) acceleration sensor for measurement of vibration is proposed. The sensor is fabricated by embedding a FBG into an aluminum cylinder, in which the optical wave propagated is coupled with the strain wave when the vibration is applied on the aluminum cylinder. The wavelength shifts of the FBG are proportional to the vibration acceleration. Employing FBG interrogation system, the wavelength shifts are converted into the change of optical power to achieve vibration measurement. Experiments indicate that the FBG acceleration sensor provides a flat frequency response from 800Hz to 5000Hz and sensitivity of 5.3mV/g at 3000Hz. The linear characteristic is good and the coefficient of determination is better than 0.996. In addition, the accuracy of the sensing system and the effect of temperature are investigated.

A fiber bragg grating acceleration sensor interrogated by a DFB laser diode

A fiber Bragg grating (FBG) acceleration sensor interrogated by a DFB laser diode is demonstrated; the sensor is fabricated by packaging a FBG on to a cantilever; the interrogation scheme takes advantage of the intensity modulation of the narrow spectral bandwidth light of a distributed feedback laser diode, when the reflection spectrum curve of a FBG moves due to the strain which is applied on the sensor. The sensor’s response to the frequency and acceleration is measured by the experiment, and the factors which have an impact on the sensor’s sensitivity are also discussed.

Four-element fiber Bragg grating acceleration sensor array

A four-element fiber Bragg grating acceleration sensor array is presented in this paper. The system combines an unbalanced Mach–Zehnder interferometer and three coarse wavelength division multiplexers (WDMs). The totally passive scheme has the advantages of high operation frequency and loose requirements for the working environment. An acceleration resolution of better than 0 . 012 m / s 2 Hz for the four channels is achieved.