Acoustic Emission Measurement by Fiber Bragg Grating Glued to Cylindrical Sensor Holder

Acoustic emission (AE) has received increased interest as a structural health monitoring (SHM) technique for various materials, including laminated polymer composites. Piezoelectric sensors, including PZT (piezoelectric ceramic) and PVDF (piezoelectric polymer), can monitor AE in materials. The thickness of the piezoelectric sensors (as low as 28 µm—PVDF) allows embedding the sensors within the laminated composite, creating a smart material. Incorporating piezoelectric sensors within composites has several benefits but presents numerous difficulties and challenges. This paper provides an overview of acoustic emission testing, concluding with a discussion on embedding piezoelectric AE sensors within fibre-polymer composites. Various aspects are covered, including the underlying AE principles in fibre-based composites, factors that influence the reliability and accuracy of AE measurements, methods to artificially induce acoustic emission, and the correlation between AE events and damage in polymer composites.

Section: Acoustic Emission (Ae)mentioning

confidence: 99%

A Review on Acoustic Emission Testing for Structural Health Monitoring of Polymer-Based Composites

Ghadarah,

Ayre

2023

“…In general, the acoustic sensitivity of polymer optical fibers is at least one order of magnitude higher than that of silica optical fibers [ 4 ]. In addition, towards the direction of exploring novel acoustic emission detection-enhancing materials, there have been efforts in altering the external coating of fused silica optical fibers in order to improve ultrasonic detection sensitivity [ 22 ] as well as novel optical fiber holder designs in order to improve omni-directional sensitivity [ 23 ].…”

Section: Introductionmentioning

confidence: 99%

Sensitivity Analysis of Acoustic Emission Detection Using Fiber Bragg Gratings with Different Optical Fiber Diameters

Violakis

Le-Quang

Shevchik

et al. 2020

Acoustic Emission (AE) detection and, in particular, ultrasound detection are excellent tools for structural health monitoring or medical diagnosis. Despite the technological maturity of the well-received piezoelectric transducer, optical fiber AE detection sensors are attracting increasing attention due to their small size, and electromagnetic and chemical immunity as well as the broad frequency response of Fiber Bragg Grating (FBG) sensors in these fibers. Due to the merits of their small size, FBGs were inscribed in optical fibers with diameters of 50 and 80 μm in this work. The manufactured FBGs were used for the detection of reproducible acoustic waves using the edge filter detection method. The acquired acoustic signals were compared to the ones captured by a standard 125 μm-diameter optical fiber FBG. Result analysis was performed by utilizing fast Fourier and wavelet decompositions. Both analyses reveal a higher sensitivity and dynamic range for the 50 μm-diameter optical fiber, despite it being more prone to noise than the other two, due to non-standard splicing methods and mode field mismatch losses. Consequently, the use of smaller-diameter optical fibers for AE detection is favorable for both the sensor sensitivity as well as physical footprint.

“…Thanks to its immunity to electromagnetic interference, high accuracy and long term stability the FBG technique has been wildly used in the fields of communication [ 1 ], dimensional metrology [ 2 ], building health monitoring [ 3 , 4 ], ultrasonic wave and vibration measurement [ 5 ], the petrochemical industry [ 6 ], and other harsh and remote environments. The sensing principle of FBG sensors involves detecting the central wavelength variation.…”

Section: Introductionmentioning

confidence: 99%

FBG Interrogation Method with High Resolution and Response Speed Based on a Reﬂective-Matched FBG Scheme

Cui

Feng

et al. 2015

In this paper, a high resolution and response speed interrogation method based on a reflective-matched Fiber Bragg Grating (FBG) scheme is investigated in detail. The nonlinear problem of the reflective-matched FBG sensing interrogation scheme is solved by establishing and optimizing the mathematical model. A mechanical adjustment to optimize the interrogation method by tuning the central wavelength of the reference FBG to improve the stability and anti-temperature perturbation performance is investigated. To satisfy the measurement requirements of optical and electric signal processing, a well- designed acquisition circuit board is prepared, and experiments on the performance of the interrogation method are carried out. The experimental results indicate that the optical power resolution of the acquisition circuit border is better than 8 pW, and the stability of the interrogation method with the mechanical adjustment can reach 0.06%. Moreover, the nonlinearity of the interrogation method is 3.3% in the measurable range of 60 pm; the influence of temperature is significantly reduced to 9.5%; the wavelength resolution and response speed can achieve values of 0.3 pm and 500 kHz, respectively.