Detection of Guided Waves in a Composite Plate Using Surface Bonded Fiber Bragg Gratings Sensor
01 Oct 2018-
Abstract: Ultrasonic guided waves based non-destructive testing (NDT) is attractive due to its potential for long range inspection. In NDT, fiber Bragg gratings (FBG) sensor is widely adopted due to its rugged wavelength encoded information and immunity to electromagnetic interference (EMI). In this paper we discuss the reception of ultrasonic guided waves in a glass fiber reinforced plastic (GFRP) composite plate using a surface bonded FBG sensor. Experimentally deduced values for wave velocity and attenuation are compared with the theoretical values.
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TL;DR: In this article , a baseline-free statistical approach for the identification and localization of delamination using sparse sampling and density-based spatial clustering of applications with noise (DBSCAN) technique is proposed.
Abstract: Delamination in composite structures is characterized by a resonant cavity wherein a fraction of an ultrasonic guided wave may be trapped. Based on this wave trapping phenomenon, we propose a baseline-free statistical approach for the identification and localization of delamination using sparse sampling and density-based spatial clustering of applications with noise (DBSCAN) technique. The proposed technique can be deployed for rapid inspection with minimal human intervention. The Performance of the proposed technique in terms of its ability to determine the precise location of such defects is quantified through the probability of detection measurements. The robustness of the proposed technique is tested through extensive simulations consisting of different random locations of defects on flat plate structures with different sizes and orientation as well as different values of signal to noise ratio of the simulated data. The simulation results are also validated using experimental data and the results are found to be in good agreement.
67 citations
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TL;DR: In this article, a fiber Bragg grating based technique was proposed to detect anomalies or defects in plate structures with transverse bends, both in the case of defect-free and transverse defects.
Abstract: Harnessing of ultrasonic guided waves confined in local features such as bends and welds, known as feature-guided waves, has emerged as a promising technique for non-destructive testing and structural health monitoring of industrial and aerospace structures. This article introduces a fiber Bragg grating based technique which uses feature-guided waves to detect anomalies or defects in plate structures with transverse bends. We are able to obtain good consistency between simulation and experimental results, both in the case of defect-free bent plates and those with transverse defects. Such results establish fiber Bragg gratings as a viable alternative to conventional techniques for structural health monitoring of bent plates.
20 citations
"Detection of Guided Waves in a Comp..." refers background in this paper
...Interrogation with ultrasonic guided waves are attractive as it provides opportunity for defect identification [6] and localization [7]....
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TL;DR: Shear horizontal guided waves are attractive for structural health monitoring applications in view of the non-dispersive behaviour of the fundamental mode, possibly higher frequencies of operation as mentioned in this paper. But they are difficult to use in practice.
Abstract: Shear horizontal guided waves are attractive for structural health monitoring applications in view of the non-dispersive behaviour of the fundamental mode, possibly higher frequencies of operation ...
17 citations
"Detection of Guided Waves in a Comp..." refers background in this paper
...The FBG sensor is surface bonded in the radial direction to the point of excitation [9]....
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...In order to interrogate the sensing information from FBG, a tunable laser is biased to the slope [9] (50....
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16 Feb 2017
TL;DR: In this article, the authors explored the use of embedded waveguides for monitoring delamination type defects in composites, which confine the wave transmission in one dimension and waves leak only through the opening provided, which enhances the capability to inspect large composite structures with very low attenuation rate.
Abstract: Aerospace & Automotive industries make extensive use of composite structures, often with complex geometries. Ultrasonic guided waves are attractive for long-range inspection of large-scale structures. However surface based transducers that are typically used, lead to two-dimensional wave propagation, limiting the applicability of guided wave methods. This work explores the use of embedded waveguides for monitoring delamination type defects in composites. These waveguides confine the wave transmission in one dimension and waves leak only through the opening provided, which enhances the capability to inspect large composite structures with very low attenuation rate. Inaccessible areas can be inspected and inter-laminar delamination detection can be achieved. Live monitoring and assessment of discontinuities can be accomplished effectively by using this mechanism.
2 citations
"Detection of Guided Waves in a Comp..." refers background in this paper
...Structural health monitoring of composites has been demonstrated through several techniques for monitoring features such delamination, stiffness of composite plates and other mechanical properties [2], [3], [4], [5], [6]....
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...Interrogation with ultrasonic guided waves are attractive as it provides opportunity for defect identification [6] and localization [7]....
[...]