A fiber Bragg grating-based smart wearable belt for monitoring knee joint postures

2019 ◽  
Vol 90 (3-4) ◽  
pp. 386-394 ◽  
Author(s):  
Zamir Ahmed Abro ◽  
Chengyu Hong ◽  
Nanliang Chen ◽  
Yifan Zhang ◽  
Rafique Ahmed Lakho ◽  
...  
Keyword(s):  
Knee Joint ◽  
Fiber Bragg Grating ◽  
Male Subject ◽  
Bend Angle ◽  
Bragg Grating ◽  
Accurate Information ◽  
Measurement Sensitivity ◽  
Static Tests ◽  
Fbg Sensors ◽  
Smart Wearable

Smart wearable technology is exceedingly desirable in athletic sports due to being lightweight, flexible to bend, soft and comfortable. It can continuously deliver accurate information and deformation. During knee flexion, the upper knee perimeter increases with the shrinkage of the knee joint flexor, and it can be monitored. In this study, a fiber Bragg grating (FBG) smart belt is fabricated by embedding FBG sensors at the center of a special silica gel (with unique adhering characteristics to fix FBG on the surface of the belt) for sensing knee joint movements. Polyvinyl chloride strips were adhered to the surface of the smart wearable belt for better protection. The smart belt was calibrated in the laboratory by a systematical changing knee posture and used to identify body postures at various static and kinematic postures of a male subject. The FBG-based smart wearable belt presented a consistent wavelength change after each step by angle changes at the knee joint position. The wavelength increment of FBG sensors increases linearly with the increasing of the bend angle of the knee joint in static tests, and the related slope ratio was 0.3 nm/°. In a jogging test, the measurement sensitivity achieved by the FBG smart wearable belt was within a range between 0.018/° and 0.021 nm/° for the male subject at the velocities of 2 and 3 km/h, respectively. The smart wearable belt could be a useful index to characterize a simple design and ease of implementation, and could also applied for knee posture circumferential strain measurements, especially for sports activities and monitoring stroke patients. This FBG smart belt can be fabricated to produce smart sensing fabrics.

Metrological Performances of Fiber Bragg Grating Sensors and Comparison with Electrical Strain Gauges

2011 ◽  
Vol 495 ◽  
pp. 53-57
Author(s):  
Marco Borotto ◽  
Enrico De Cais ◽  
Marco Belloli ◽  
Andrea Bernasconi ◽  
Stefano Manzoni
Keyword(s):  
Fiber Bragg Grating ◽  
Thermal Effects ◽  
Measurement Accuracy ◽  
Signal To Noise Ratio ◽  
Bragg Grating ◽  
Light Spectrum ◽  
Static Tests ◽  
Measurement Systems ◽  
Fiber Bragg Grating Sensors ◽  
Fbg Sensors

The fiber Bragg grating sensors (FBGs) have been recently introduced: they present a photorecord grating on the fiber itself, which allows the reflection of a certain wavelength of the input light spectrum. The applied strain is estimated relying on changes of the reflected wavelength. One of the possible applications that has prompted us to study this type of sensors is the possibility to create smart dynamometric structures based on carbon fiber by embedding FBGs. Many papers are available in literature about some applications with smart structures but there is not yet an appropriate metrological characterization about these FBG sensors, their strengths and weaknesses: for these reasons it was deemed useful making several tests on FBG sensors in terms of measurement accuracy, signal to noise ratio, ability to compensate for thermal effects and their behavior for dynamic applications. All these results have been compared to electrical strain gauge ones, which represent the actual reference strain measurement systems. The various solutions to compensate for thermal effects have offered several information for further analyses and the basis for a future use of these sensors for static or semi-static tests. Being fully aware of FBGs characteristics allows to draw down guidelines about their integration in composite materials for the most different applications, understanding in a better way the sensor response.

An FBG-based smart wearable ring fabricated using FDM for monitoring body joint motion

2019 ◽  
pp. 152808371987020 ◽  
Author(s):  
Hong Cheng-Yu ◽  
Zamir Ahmed Abro ◽  
Zhang Yi-Fan ◽  
Rafique Ahmed Lakho
Keyword(s):  
Knee Joint ◽  
Fiber Bragg Grating ◽  
Polylactic Acid ◽  
Elbow Joint ◽  
Fused Deposition Modeling ◽  
Bragg Grating ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
Smart Wearable ◽  
Body Joint

This study proposed a new fiber Bragg grating-based smart ring for monitoring body joint postures occurred at elbow joint and knee joint positions. A single-mode fiber Bragg grating sensor was embedded into a 3D printed ring for sensing occurred deformation of the ring. The raw material used for fabricating the smart ring was polylactic acid, which was found to have the advantages of being flexible in nature and having ease of fabrication using fused deposition modeling method. The fabrication process of the fiber Bragg grating smart ring was characterized by the advantages of ease of handling, quick prototyping, high resolution, low cost, and time-saving. Bare fiber Bragg grating sensors were successfully embedded into hot printed polylactic acid material during the fused deposition modeling process, even the printing temperature of the printing nozzle exceeded 200℃. Two new smart wearable rings were fabricated and used to monitor systematic bend motion of elbow joint and knee joint. The measurement sensitivities of the two smart rings mounted at the elbow joint and knee joint were 0.0056 nm/° and 0.0276 nm/°, respectively. The corresponding maximum measurement angle within current calibration tests were 90° and 100°, respectively. The method of using both fiber Bragg grating and fused deposition modeling for sensor design can be extended for the fabrication of other sensors such as temperature sensors, strain sensors, pressure sensors, stress sensors, displacement sensors, and tilt sensors.

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.

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.

scholarly journals Study on the Optimal Groove Shape and Glue Material for Fiber Bragg Grating Measuring Bolts

Sensors ◽  
2018 ◽  
Vol 18 (6) ◽  
pp. 1799 ◽  
Author(s):  
Yiming Zhao ◽  
Nong Zhang ◽  
Guangyao Si ◽  
Xuehua Li
Keyword(s):  
Fiber Bragg Grating ◽  
Linear Regression Analysis ◽  
Tensile Load ◽  
Tensile Tests ◽  
Bragg Grating ◽  
Engineering Practice ◽  
Direct Tension ◽  
Groove Shape ◽  
Fbg Sensors ◽  
The Impact

Fiber Bragg grating (FBG) measuring bolts, as a useful tool to evaluate the behaviors of steel bolts in underground engineering, can be manufactured by gluing the FBG sensors inside the grooves, which are usually symmetrical cuts along the steel bolt rod. The selection of the cut shape and the glue types could perceivably affect the final supporting strength of the bolts. Unfortunately, the impact of cut shape and glue type on bolting strength is not yet clear. In this study, based on direct tension tests, full tensile load–displacement curves of rock bolts with different groove shapes were obtained and analyzed. The effects of groove shape on the bolt strength were discussed, and the stress redistribution in the cross-section of a rock bolt with different grooves was simulated using ANSYS. The results indicated that the trapezoidal groove is best for manufacturing the FBG bolt due to its low reduction of supporting strength. Four types of glues commonly used for the FBG sensors were assessed by conducting tensile tests on the mechanical testing and simulation system and the static and dynamic optical interrogators system. Using linear regression analysis, the relationship between the reflected wavelength of FBG sensors and tensile load was obtained. Practical recommendations for glue selection in engineering practice are also provided.

scholarly journals Stress Monitoring on GFRP Anchors Based on Fiber Bragg Grating Sensors

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1507 ◽  
Author(s):  
Hai-Lei Kou ◽  
Wang Li ◽  
Wang-Chun Zhang ◽  
Yuan Zhou ◽  
Xiao-Long Zhou
Keyword(s):  
Fiber Bragg Grating ◽  
Field Test ◽  
Weight Ratio ◽  
Electromagnetic Properties ◽  
Bragg Grating ◽  
Shear Stresses ◽  
Stress Profile ◽  
Stress Monitoring ◽  
Axial Forces ◽  
Fbg Sensors

Glass fiber-reinforced polymer (GFRP) bolts have been widely used in some applications of grouted anchors because of the advantages of better resistance to corrosion, high strength-to-weight ratio, low electromagnetic properties, and so on. This study presents a field test to assess the feasibility of fiber Bragg grating (FBG) sensors in monitoring the stress profile of GFRP anchors during pulling test. Two GFRP anchors were fully instrumented with FBG sensors and then installed into the ground using a drilling and grouting method. To measure the stress profile along test anchors, seven bare FBG sensors were arranged in a single optical fiber and then embedded in the middle of GFRP bolts in the process of extrusion molding. The procedure for embedding bare FBG sensors into GFRP bolts is introduced first. Then, the axial forces and shear stresses that were calculated from the measurements of the FBG sensors are discussed. The field test results indicate that the embedded FBG technology was feasible to monitor the stress state of GFRP anchors during pulling.

scholarly journals A Fiber Bragg Grating Based Torsional Vibration Sensor for Rotating Machinery

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2669 ◽  
Author(s):  
Jingjing Wang ◽  
Li Wei ◽  
Ruiya Li ◽  
Qin Liu ◽  
Lingling Yu
Keyword(s):  
Optical Fiber ◽  
Fiber Bragg Grating ◽  
Torsional Vibration ◽  
Electromagnetic Interference ◽  
Vibration Sensor ◽  
Vibration Measurement ◽  
Bragg Grating ◽  
Structural Parameter ◽  
Measurement Sensitivity ◽  
Fiber System

This paper proposes a new type of torsional vibration sensor based on fiber Bragg grating (FBG). The sensor has two mass ball optical fiber systems. The optical fiber is directly treated as an elastomer and a mass ball is fixed in the middle of the fiber in each mass ball fiber system, which is advantageously small, lightweight, and has anti-electromagnetic interference properties. The torsional vibration signal can be calculated by the four FBGs’ wavelength shifts, which are caused by mass balls. The difference in the two sets of mass ball optical fiber systems achieves anti-horizontal vibration and anti-temperature interference. The principle and model of the sensor, as well as numerical analysis and structural parameter design, are introduced. The experimental conclusions show that the minimum torsional natural frequency of the sensor is 27.35 Hz and the torsional vibration measurement sensitivity is 0.3603 pm/(rad/s2).

Detection of missing fastener based on vibration mode analysis using fiber Bragg grating (FBG) sensors

2003 ◽  
Author(s):  
Akiyoshi Shimada ◽  
Kei Urabe ◽  
Yoshihiro Kikushima ◽  
Jun Takahashi ◽  
Kazuro Kageyama
Keyword(s):  
Fiber Bragg Grating ◽  
Vibration Mode ◽  
Mode Analysis ◽  
Bragg Grating ◽  
Fbg Sensors
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