Application of fiber Bragg grating sensors to real-time strain measurement of cryogenic tanks

2003 ◽  
Author(s):  
Nobuo Takeda ◽  
Tadahito Mizutani ◽  
Kentaro Hayashi ◽  
Yoji Okabe
Keyword(s):  
Fiber Bragg Grating ◽  
Real Time ◽  
Strain Measurement ◽  
Bragg Grating ◽  
Fiber Bragg Grating Sensors ◽  
Cryogenic Tanks

scholarly journals Real-Time Train Wheel Condition Monitoring by Fiber Bragg Grating Sensors

2011 ◽  
Vol 8 (1) ◽  
pp. 409048 ◽  
Author(s):  
Chuliang Wei ◽  
Qin Xin ◽  
W. H. Chung ◽  
Shun-yee Liu ◽  
Hwa-yaw Tam ◽  
...  
Keyword(s):  
Fiber Bragg Grating ◽  
Real Time ◽  
Visual Inspection ◽  
Condition Index ◽  
Bragg Grating ◽  
Time System ◽  
Real Time System ◽  
Fiber Bragg Grating Sensors ◽  
Extensive Field ◽  
The Cost

Wheel defects on trains, such as flat wheels and out-of-roundness, inevitably jeopardize the safety of railway operations. Regular visual inspection and checking by experienced workers are the commonly adopted practice to identify wheel defects. However, the defects may not be spotted in time. Therefore, an automatic, remote-sensing, reliable, and accurate monitoring system for wheel condition is always desirable. The paper describes a real-time system to monitor wheel defects based on fiber Bragg grating sensors. Track strain response upon wheel-rail interaction is measured and processed to generate a condition index which directly reflects the wheel condition. This approach is verified by extensive field test, and the preliminary results show that this electromagnetic-immune system provides an effective alternative for wheel defects detection. The system significantly increases the efficiency of maintenance management and reduces the cost for defects detection, and more importantly, avoids derailment timely.

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.

Experimental analysis of the response of fiber Bragg grating sensors under non-uniform strain field in a twill woven composite

2018 ◽  
Vol 53 (7) ◽  
pp. 893-908 ◽  
Author(s):  
M Kharshiduzzaman ◽  
A Gianneo ◽  
A Bernasconi
Keyword(s):  
Composite Materials ◽  
Digital Image Correlation ◽  
Fiber Bragg Grating ◽  
Digital Image ◽  
Strain Measurement ◽  
Strain Field ◽  
Image Correlation ◽  
Bragg Grating ◽  
Fiber Bragg Grating Sensors ◽  
T Matrix

Fiber Bragg grating optical sensors are nowadays widely employed for strain measurement for structural health monitoring and in experimental mechanics. Compared to other techniques, i.e. electrical strain gauges, fiber Bragg grating offer immunity to electromagnetic interference and allow for long transmission lead lines. Moreover, thanks to multiplexing interrogation, several sensors can be photo-imprinted into a single fiber core allowing for strain evaluation at multiple locations simultaneously. They have high adaptability to composite materials, particularly because it is possible to be embedded into laminates without affecting their strength and stiffness. Fiber Bragg grating strain measurements are based on the detection of the wavelength shift of their peak reflected spectrum. However, subjected to strain gradients, the spectral response of fiber Bragg grating sensors may be distorted and the sharp peak may not be retained. In this work, the response of fiber Bragg grating sensors having different grating lengths and bonded to the surface of a carbon fiber-reinforced twill woven laminate was analyzed. The analysis combined transfer matrix (T-matrix) with digital image correlation methods. Digital image correlation technique was used to capture the non-uniform strain fields in the woven composites and measured strains were employed in T-Matrix algorithm to simulate fiber Bragg grating response. Using this approach, the effect of the length of the fiber Bragg grating on the strain measurement is assessed and results discussed. Moreover, it is shown that T-matrix formulation combined with a non-contact strain field measurement technique, as DIC, is an appropriate technique to simulate the behavior of fiber Bragg grating bonded to composite materials of complex microstructure.

Sign in / Sign up

Export Citation Format

Share Document