A theoretical/numerical study on ultrasound wave coupling from structure to remotely bonded fiber Bragg grating (FBG) ultrasound sensor

2020 ◽  
pp. 1-31
Author(s):  
Haiying Huang ◽  
Kranthi Balusu
Keyword(s):  
Optical Fiber ◽  
Numerical Study ◽  
Longitudinal Mode ◽  
Propagation Speed ◽  
Ultrasound Wave ◽  
Ultrasound Waves ◽  
Time Frequency ◽  
Bonding Parameters ◽  
Ultrasound Sensor ◽  
Fbg Sensors

Abstract Recent published experimental works on remotely bonded FBG ultrasound sensors show that they display some unique characteristics that are not observed with directly bonded FBG sensors. These studies suggest that the bonding of the optical fiber strongly influences how the ultrasound waves are coupled from the structure to the FBG sensor. In this paper, the analytical model of the structure-adhesive-optical fiber section, treated as an ultrasound coupler, is derived and analyzed to explain the observed experimental phenomena. The resulting dispersion curve shows that the ultrasound coupler possesses a cut-off frequency, above which a dispersive longitudinal mode exists. The low propagation speed of the dispersive longitudinal mode leads to multiple resonances at and above the cut-off frequency. To characterize the resonant characteristics of the ultrasound coupler, a semi-analytical numerical model is implemented and the scattering parameters (S-parameters) are introduced for broadband time-frequency analysis. The simulation was able to reproduce the experiment observations reported by other researchers. Parametric studies conducted on the bonding parameters demonstrated that the behaviors of the remotely bonded FBG sensors can be explained based on its resonant characteristics.

A Multiple Fiber Grating Sensor System Using Code Division Multiple Access

2013 ◽  
Vol 765-767 ◽  
pp. 2444-2447 ◽  
Author(s):  
Wei Li ◽  
Yong Jia Zhang ◽  
Hong Qiao Wen
Keyword(s):  
Optical Fiber ◽  
Fiber Bragg Grating ◽  
Code Division Multiple Access ◽  
Multiple Access ◽  
Simulation Experiment ◽  
Fiber Grating ◽  
Sensing System ◽  
Fiber Grating Sensor ◽  
Fbg Sensors ◽  
Code Division Multiple

In order to increase the multiplying density of Fiber Bragg Grating (FBG) sensors, a novel FBG Sensing System based on CDMA technology has been developed. Simulation experiment indicates the CDMA technology combine with optical fiber grating sensing system together successfully. Furthermore, the system can distinguishes the FBG and enhance the FBG network band utilization.

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).

scholarly journals Long-Distance Time Transfer in Optical Fiber Networks Using a Cascaded Taming Technology

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Ding Chen ◽  
Jiangning Xu ◽  
Yifeng Liang ◽  
Shan Jiang ◽  
Hongyang He
Keyword(s):  
Optical Fiber ◽  
High Precision ◽  
Wavelength Division Multiplexing ◽  
Time Synchronization ◽  
Atomic Clock ◽  
Process Time ◽  
Long Distance ◽  
Time Service ◽  
Time Frequency ◽  
Fiber Link

In order to meet the time service needs of high-precision, long-distance, and multinode optical network, this paper proposes a new time synchronization solution, which combines the wavelength division multiplexing (WDM) technology with cascaded taming clock technology. The WDM technology is used for time synchronization between each pair of master-slave nodes. In the system, there are two wavelengths on the fiber link between the master node and the slave node for transmitting signals. 1 plus per second (PPS) signal, time code signal, and 10 MHz signal are, respectively, and successively, sent to the optical fiber link. By solving the one-way delay through analysis of error contribution and link characteristics of the time transmission process, time synchronization of the master-slave nodes pair is achieved. Furthermore, the authors adopt cascaded taming clock technology to ensure accurate time synchronization of each node. A 700 km long-distance time-frequency synchronization system is constructed in the laboratory. The system uses a cesium atomic clock as the reference clock source and transmits the signals through 8 small rubidium atomic clocks (RB clocks) hierarchically. Results from the experiment show that the long-term time stability is 47.5 ps/104 s. The system’s structural characteristics and the experiment results meet the requirements to allow practical use of high-precision time synchronization in networks. This proposed solution can be applied in various civil, commercial, and military fields.

Scaled Acoustics Experiments and Vibration Prediction Based Structural Health Monitoring

2008 ◽  
Author(s):  
Nesrin Sarigul-Klijn ◽  
Israel Lopez ◽  
Seung-Il Baek
Keyword(s):  
Health Monitoring ◽  
Dimensional Reduction ◽  
Structural Damage ◽  
Numerical Study ◽  
Damage Index ◽  
Time Frequency ◽  
Structural Health ◽  
Reduction Techniques ◽  
Vibration Prediction ◽  
Dimensional Reduction Techniques

Vibration and acoustic-based health monitoring techniques are presented to monitor structural health under dynamic environment. In order to extract damage sensitive features, linear and nonlinear dimensional reduction techniques are applied and compared. First, a vibration numerical study based on the damage index method is used to provide both location and severity of impact damage. Next, controlled scaled experimental measurements are taken to investigate the aeroacoustic properties of sub-scale wings under known damage conditions. The aeroacoustic nature of the flow field in and around generic aircraft wing damage is determined to characterize the physical mechanism of noise generated by the damage and its applicability to battle damage detection. Simulated battle damage is investigated using a baseline, and two damage models introduced; namely, (1) an undamaged wing as baseline, (2) chordwise-spanwise-partial-penetration (SCPP), and (3) spanwise-chordwise-full-penetration (SCFP). Dimensional reduction techniques are employed to extract time-frequency domain features, which can be used to detect the presence of structural damage. Results are given to illustrate effectiveness of this approach.

Event Discrimination Method for Distributed Optical Fiber Intrusion Sensing System Based on Integrated Time/Frequency Domain Feature Extraction

2019 ◽  
Vol 39 (6) ◽  
pp. 0628002 ◽  
Author(s):  
彭宽 Kuan Peng ◽  
冯诚 Cheng Feng ◽  
王森懋 Senmao Wang ◽  
艾凡 Fan Ai ◽  
李豪 Hao Li ◽  
...  
Keyword(s):  
Feature Extraction ◽  
Optical Fiber ◽  
Frequency Domain ◽  
Time Frequency ◽  
Sensing System ◽  
Distributed Optical Fiber ◽  
Discrimination Method

The Role of Gold Nanoparticles in Sonosensitization of Human Cervical Carcinoma Cell Line under Ultrasound Irradiation: An In Vitro Study

2019 ◽  
Vol 59 ◽  
pp. 1-14 ◽  
Author(s):  
Ahmad Shanei ◽  
Hadi Akbari-Zadeh ◽  
Hamid Fakhimikabir ◽  
Neda Attaran
Keyword(s):  
Gold Nanoparticles ◽  
Hela Cells ◽  
Ultrasound Irradiation ◽  
Ultrasound Wave ◽  
Efficient Treatment ◽  
Ultrasound Waves ◽  
Cervical Carcinoma Cell Line ◽  
Ultrasound Intensity ◽  
High Concentrations

Abstract:Purpose: The objective of this investigation was to evaluate the combined effects of ultrasound irradiation as a non-invasive and non-ionizing radiation with gold nanoparticles as ultrasound sensitizers on the HeLa cells.Materials and Methods: First, Gold nanoparticles (GNPs) were prepared, and the characterizations of nanoparticles were analyzed using TEM and UV-vis. Different concentrations of nanoparticles (0.2, 1, 5, 25 and 50 μg/ml) were used. Then, cytotoxicity of the GNPs was studied on HeLa cells, and finally concentrations of 0.2, 1 and 5 µg/mL were chosen for supplementary studies. The effects of nanoparticles and ultrasound irradiation with different intensities (0.5, 1 and 1.5 W/cm2) as well as the combination of ultrasound radiation with various concentrations of nanoparticles on 24, 48 and 72 h post-experiment cells’ viability were estimated by MTT and trypan blue assay.Results: Results showed that the sonosensitizing effect of nanoparticles mainly depended on the intensity of ultrasound waves and the concentration of GNPs. By increasing the concentration of GNPs and ultrasound intensity, the nanoparticle's effect of sensitizer was also increased. Moreover, as expected, the highest effect was observed at the highest intensities (1.5 W/cm2) of ultrasound wave and high concentrations (5 μg/ml) of GNPs 72 h after exposure to ultrasound irradiation.Conclusions: It is revealed that GNPs can be used as sonosensitizers of HeLa cells to ultrasound irradiation in order to produce an efficient treatment.

Experimental and Numerical Study of Oil Whip in Propeller Shaft

2019 ◽  
Author(s):  
Adarsh Divakaran ◽  
K. Vijayan ◽  
A. Kartheek
Keyword(s):  
Experimental Study ◽  
Numerical Study ◽  
Beam Theory ◽  
Operating Regime ◽  
Propeller Shaft ◽  
Hydrodynamic Bearing ◽  
Time Frequency ◽  
Oil Whip ◽  
Run Up ◽  
Stiffness And Damping

Abstract An experimental study and theoretical study is carried out to understand the vibration signature of a propeller shaft. A test rig consists of a rotor shaft and three-disc supported on hydrodynamic bearing was analyzed. Presence of hydrodynamic bearing makes the systems natural frequency speed dependent. A theoretical model of the rotor disc system was developed using FEM. The rotor was formulated on Euler–Bernoulli beam theory. Proportional damping was assumed for the shaft. The stiffness and damping coefficients of the bearing are calculated by short bearing assumption. A Campbell diagram was plotted to observe the variation in natural frequencies with rotational speed. There was an indication of mode approaching each other with a speed which could result in the self-excited phenomena such as “Oil whip”. The hydrodynamic forces in the fluid film produce Oil whip. The presence of Oil whip was ascertained by carrying out the experimental study. The time-frequency plot during the run-up indicated the presence of a whip. The study indicated the influence of modes on the whip phenomena. This can be used in forming guidelines for the safe operating regime for the propeller shaft.

Numerical study of the evanescent field coupling effect on two optical fiber sensors

2019 ◽  
Author(s):  
Nursyahida M. Hasan ◽  
K. N. Mutter ◽  
M. Z. Matjafri ◽  
H. San Lim ◽  
S. Yeoh ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Coupling Effect ◽  
Numerical Study ◽  
Optical Fiber Sensors ◽  
Evanescent Field ◽  
Fiber Sensors ◽  
Field Coupling

A smart insole for monitoring plantar pressure based on the fiber Bragg grating sensing technique

2019 ◽  
Vol 89 (17) ◽  
pp. 3433-3446 ◽  
Author(s):  
Rafique Ahmed Lakho ◽  
Zhang Yi-Fan ◽  
Jiang Jin-Hua ◽  
Hong Cheng-Yu ◽  
Zamir Ahmed Abro
Keyword(s):  
Optical Fiber ◽  
Pressure Distribution ◽  
Fiber Bragg Grating ◽  
Plantar Pressure ◽  
Bragg Grating ◽  
Body Postures ◽  
Plantar Pressure Distribution ◽  
The Subject ◽  
Fbg Sensors ◽  
Smart Insole

The analysis of plantar pressure distribution is essential in the field of biomedical and sports-related applications. In this study, a smart insole was developed for the measurement of plantar pressure distribution and the evaluation of body postures using optical fiber Bragg grating (FBG) sensing technology. Four FBG sensors characterized by four different center Bragg wavelengths, 1528 ± 0.3, 1532 ± 0.3, 1535 ± 0.3 and 1539 ± 0.3 nm, were located at the first metatarsus, third metatarsus, fifth metatarsus and heel position, respectively. The measurement sensitivity of all the FBG sensors was 0.000412 nm/kPa, approximately. Silica gel material of modulus = 10 MPa was selected to incorporate the FBG sensors. All FBG sensors were multiplexed together with one optical fiber cable. The performance and functional properties of all FBG-based pressure sensors were calibrated in the laboratory to evaluate plantar pressure distribution. A male subject was selected for performing four tasks, namely standing in an upright position, leaning forward, squat position and forward fold. During standing tests, plantar pressure observed at the heel position was around 57% higher than that at the first and third metatarsus, while the pressure of the fifth metatarsus position presents minimal pressure, which is only 37% that of the pressure of the heel position. When the subject performs leaning forward, the squat position and forward fold posture, the first and third metatarsi show maximum pressure, while the pressure decreases at the fifth metatarsus position. However, almost zero pressure is observed at the heel position when the subject changes the body postures of leaning forward, squat and forward fold posture. The extreme pressure of the forward fold posture was 1750 kPa acquired at the first metatarsus, which is 52% and 62% higher than those at the fifth and third metatarsi, respectively. Therefore, the smart insole successfully recorded both plantar pressure distribution and body posture changes regarding the wavelength values collected by the FBG sensors.

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