Versatile fiber-Bragg grating arrays for strain mapping and ultrasound Lamb wave detection

Author(s):  
G. Thursby ◽  
D. C. Betz ◽  
B. Culshaw ◽  
W. J. Staszewski
2011 ◽  
Author(s):  
Nick Miesen ◽  
Yoshihiro Mizutani ◽  
Roger M. Groves ◽  
Jos Sinke ◽  
Rinze Benedictus

2018 ◽  
Vol 18 (1) ◽  
pp. 334-344 ◽  
Author(s):  
Zhenhua Tian ◽  
Lingyu Yu ◽  
Xiaoyi Sun ◽  
Bin Lin

Fiber Bragg gratings are known being immune to electromagnetic interference and emerging as Lamb wave sensors for structural health monitoring of plate-like structures. However, their application for damage localization in large areas has been limited by their direction-dependent sensor factor. This article addresses such a challenge and presents a robust damage localization method for fiber Bragg grating Lamb wave sensing through the implementation of adaptive phased array algorithms. A compact linear fiber Bragg grating phased array is configured by uniformly distributing the fiber Bragg grating sensors along a straight line and axially in parallel to each other. The Lamb wave imaging is then performed by phased array algorithms without weighting factors (conventional delay-and-sum) and with adaptive weighting factors (minimum variance). The properties of both imaging algorithms, as well as the effects of fiber Bragg grating’s direction-dependent sensor factor, are characterized, analyzed, and compared in details. The results show that this compact fiber Bragg grating array can precisely locate damage in plates, while the comparisons show that the minimum variance method has a better imaging resolution than that of the delay-and-sum method and is barely affected by fiber Bragg grating’s direction-dependent sensor factor. Laboratory tests are also performed with a four–fiber Bragg grating array to detect simulated defects at different directions. Both delay-and-sum and minimum variance methods can successfully locate defects at different positions, and their results are consistent with analytical predictions.


2005 ◽  
Author(s):  
Yan Zhang ◽  
Sanguo Li ◽  
Z. Yin ◽  
Robert Pastore, Jr. ◽  
Kurt O'Donnell ◽  
...  

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1375 ◽  
Author(s):  
Chunfang Rao ◽  
Lingze Duan

Lamb wave (LW) is well suited for structural health monitoring (SHM) in advanced composites. However, characteristic differences between the symmetric modes and the anti-symmetric modes often add complexity to SHM systems. The anisotropic nature of composite materials, on the other hand, necessitates direction-sensitive sensing. In this paper we report the experimental demonstration of bidirectional (0° and 90°), bimodal (S0 and A0) LW measurement within the frequency range of 20–140 kHz using a polarization-maintaining fiber Bragg grating (PM-FBG) sensor attached to a composite laminated plate. By selectively interrogating the fast and/or the slow axis of the PM-FBG, we show that not only can the sensor respond to LWs propagating along both directions, but the response can also be used to differentiate the two directions. Moreover, the fast axis of the sensor is able to respond to both the S0 and the A0 modes when the sensor is aligned with the wave propagation direction, whereas single S0 mode response can be achieved with the slow axis operating perpendicularly to the wave propagation direction. Such diverse responses indicate the potential of PM-FBGs as versatile multi-parameter SHM detectors, which can effectively address the challenges posed by material anisotropicity and LW mode diversity.


2016 ◽  
Author(s):  
Junghyun Wee ◽  
Drew Hackney ◽  
Kara Peters ◽  
Brian Wells ◽  
Philip Bradford

2018 ◽  
Vol 14 (07) ◽  
pp. 62
Author(s):  
Cai Li ◽  
Hunag Xiao ◽  
Zuo Xiaoqiong

Lamb wave is widely acknowledged as one of the most encouraging tools for damage identification in plate structures, and relevant research has been conducted intensively. However Lamb wave modes have different wave structure, frequency dispersion and attenuation characteristics, which are sensitivity to different types of damages and it is difficult to solve such engineering problems by conventional techniques. Although the single pattern detection method has been researched by piezoelectric wafers, there is little research about FBG sensing detection under single-mode ultrasonic Lamb wave technique currently. So this paper puts forward a single-mode Lamb wave technique for crack detection based on Fiber Bragg Grating sensor, which is used to receive the waves in the plate. First of all, measuring principle of single-mode ultrasonic Lamb technique and demodulation principle of the FBG sensor are introduced. And simulation analysis in the acoustic field is devoted, whose results lay the foundation for the damage detection in the plate. Then, the experimental system is built by a single-mode Lamb wave excitation, and the feasibility of fiber Bragg grating sensors in single-mode excitation method is verified by experiments.


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