Ultrasonic Structural Health Monitoring Using Fiber Bragg Grating

Wu, Qi; Okabe, Yoji; Yu, Fengming

doi:10.3390/s18103395

Cited by 76 publications

(58 citation statements)

References 138 publications

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“…Unfortunately, in their conventional configuration based on change in the wavelength, their sensitivity to GW is very low. In order to overcome this low sensitivity a novel approach of employing the FBG sensor in the edge filtering configuration has been proposed [ 8 ]. The edge filtering approach makes use of amplitude based detection and allows signal amplification which improves the sensitivity of FBG sensors to GW.…”

Section: Introductionmentioning

confidence: 99%

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A Two-Step Guided Waves Based Damage Localization Technique Using Optical Fiber Sensors

Soman

Balasubramaniam

Golestani

et al. 2020

Sensors

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Structural health monitoring (SHM) systems help in reducing maintenance cost and avoiding catastrophic failure of the structure. As a result, they have been a focus of research for the past few decades. Ideally, the methods employed should be low cost and able to detect and localize small levels of damage reliably and accurately. This paper describes a guided waves (GW) based two-step technique for damage detection and localization using fiber Bragg grating (FBG) sensors. The FBG sensors offer benefits such as the ability to be embedded and multiplexed as well as being lightweight and insensitive to electric and magnetic fields, and they have long been seen as a promising solution for the GW measurements in structures. Unfortunately, in the conventional wavelength-based interrogation they have very low signal to noise ratio and as a result low sensitivity. Therefore, the FBG sensor is incorporated in the edge filtering configuration. The major challenges in the use of FBG sensors for GW-based detection are their directional sensitivity and passive nature. The passive nature leads to the reduction in the available actuator–sensor (AS) pairs while the directionality makes the signal processing a challenge. The proposed two-step methodology overcomes these shortcomings of FBG sensors. In the first step the amplitude weighted elliptical approach is used to identify the hotspots due to the inadequate number of AS pairs, the elliptical approach is not sufficient for damage localization. Therefore, in order to further localize the damage the edge reflection based ray-tracing approach is implemented in the second step. Through the two step method, the damage is accurately located. The paper provides the proof of concept of the proposed methodology on an aluminum plate with simulated damage. The results indicate, that indeed the two-step methodology allows accurate damage localization and overcomes the possibility of false detections.

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Section: Introductionmentioning

confidence: 99%

“…The edge filtering approach makes use of amplitude based detection and allows signal amplification which improves the sensitivity of FBG sensors to GW. The edge filtering approach has been explained in detail in [ 8 , 9 ].…”

Section: Introductionmentioning

confidence: 99%

A Two-Step Guided Waves Based Damage Localization Technique Using Optical Fiber Sensors

Soman

Balasubramaniam

Golestani

et al. 2020

Sensors

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“…Fiber Bragg gratings (FBGs), have been widely applied for the detection of Lamb waves for structural health monitoring applications [1]. There are many advantages to using FBG sensors, as compared to conventional piezo-ceramic (PZT) sensors, for the detection of Lamb waves.…”

Section: Introductionmentioning

confidence: 99%

“…There are many advantages to using FBG sensors, as compared to conventional piezo-ceramic (PZT) sensors, for the detection of Lamb waves. These include the fact that a large number of FBGs can be multiplexed in a single optical fiber, the durability of silica in corrosive environments, and the immunity of FBGs to electromagnetic interference [1]. Further, FBG sensors can be closely spaced, allowing the separation of acoustic modes in the detected signals [2].…”

Section: Introductionmentioning

confidence: 99%

Ultrasonic Lamb wave measurement sensitivity of aligned carbon nanotube coated fiber Bragg grating

et al. 2019

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Fiber Bragg grating (FBG) sensors are typically bonded on the surface of a structure using an adhesive to collect ultrasonic waves for damage detection in structural health monitoring applications. However, the ultrasonic wave transfer from structure to optical fiber suffers signal attenuation due to the adhesive bond layer, which has a significantly different acoustic impedance than the optical fiber. Therefore, this paper develops a systematic procedure to fabricate an aligned carbon nanotube (CNT)-wrapped FBGs for acoustic impedance matching. Specifically, we first develop an automated CNT winding system to fabricate CNT-wrapped FBGs with varying CNT layer thickness, which are bonded to an aluminum plate for ultrasonic sensitivity testing. We demonstrate that CNT wrapped FBGs do not necessarily produce an increased sensitivity as compared to a reference polyimide-coated FBG, however some outliers are observed with a significant improvement. Using a scanning electron microscopy we examine the cross-section of CNT/adhesive layers, identifying a unique CNT/ adhesive bonding morphology with a stiff exterior shell and a relatively compliant inner layer. Finite element simulation validates that this two-layered bonding geometry is most likely the source of the increased FBG ultrasonic sensitivity for the outliers.

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“…Одним из актуальных направлений в области волоконно-оптических датчиков являются детектирование акустических возмущений в конструкциях, в частности, при диагностике композитных материалов [3]. В таких измерительных системах в качестве чувствительного элемента может выступать однородная ВБР, ВБР с фазовым сдвигом в структуре, а также интерферометр Фабри-Перо на основе ВБР.…”

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