Statistical partial wavefield imaging using Lamb wave signals

Harley, Joel B.; Chia, Chen Ciang

doi:10.1177/1475921717727160

Cited by 24 publications

(19 citation statements)

References 53 publications

(99 reference statements)

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“…9–16 This wave field data are also beneficial for the verification of image processing tools for acoustic wave field analysis and spectroscopy. 17–22 Section “Guided wave measurements part II: SHM measurements” presents the SHM measurements of the CFRP plate at constant temperature where a surface-mounted reversible defect model was placed at several positions on the structure. Multiple frequencies were recorded in a round-robin fashion at each structural condition.…”

Section: Introductionmentioning

confidence: 99%

Open Guided Waves: online platform for ultrasonic guided wave measurements

Moll

Kathol

Fritzen

et al. 2018

Structural Health Monitoring

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Ultrasonic guided waves have been used successfully in structural health monitoring systems to detect damage in isotropic and composite materials with simple and complex geometry. A limitation of current research is given by a lack of freely available benchmark measurements to comparatively evaluate existing methods. This article introduces the extendable online platform Open Guided Waves ( http://www.open-guided-waves.de ) where high-quality and well-documented datasets for guided wave-based inspections are provided. In this article, we describe quasi-isotropic carbon-fiber-reinforced polymer plates with embedded piezoelectric transducers as a first benchmark structure. Intentionally, this is a structure of medium complexity to enable many researchers to apply their methods. In a first step, ultrasound and X-ray measurements were acquired to verify pristine conditions. Next, mechanical testing was done to determine the stiffness tensor and sample density based on standard test procedures. Guided wave measurements were divided into two parts: first, acoustic wave fields were acquired for a broad range of frequencies by three-dimensional scanning laser Doppler vibrometry. Second, structural health monitoring measurements in the carbon-fiber-reinforced polymer plate were collected at constant temperature using a distributed transducer network and a surface-mounted reversible defect model. Initial results serving as validation are presented and discussed.

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Section: Introductionmentioning

confidence: 99%

Open Guided Waves: online platform for ultrasonic guided wave measurements

Moll

Kathol

Fritzen

et al. 2018

Structural Health Monitoring

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“…introduced an expedition to the acquisition process of ultrasonic wavefield data [8,[14][15][16][17][18]. Di Ianni et al.…”

Section: Introductionmentioning

confidence: 99%

“…[15] demonstrated that the signal decomposition based on the Fourier domain has better recovery accuracy with less than 34% of the original sampling grid. Harley and Chia [17] introduced a framework to use sparse wavenumber analysis based on CS [18] to create a damage-free model of the wavefield. As a result, these methods improved the scan time of current wavefield imaging.…”

Section: Introductionmentioning

confidence: 99%

Spatial ultrasonic wavefront characterization using a laser parametric curve scanning method

Chong

Todd

2021

Ultrasonics

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Ultrasonic wavefield imaging (UWI) provides insightful spatial information about ultrasonic wave propagation in planar (2-D) space for nondestructive evaluation and structural health monitoring (NDE-SHM) applications. In all materials, the wavefronts of the incident and reflected waves propagate with unique patterns that may be represented by parametrized polar curves in 2-D geometric space. In this paper, a spatial ultrasonic wavefront characterization method based on a parametric curve laser scan is proposed to characterize the spatial ultrasonic wavefront for both isotropic and anisotropic materials. Three parametric curves (circular, hyperbolic, and cyclicharmonic curves) were considered. Two wavefront characterization process were carried out, namely (i) deciding the parametric equation of the closed-form geometric plane curve via UWI, and (ii) measuring and updating the ultrasound via laser ultrasonic interrogation system (LUIS) and quantifying the values(s) of the predicted parametric curve equation using a temporal crosscorrelation technique. The proposed method was tested on pristine aluminum and cross-ply CFRP plates to characterize the spatial incident and reflected wavefronts of the plates. The non-fiber direction region () and the fiber direction region () of the cross-ply CFRP plate were considered in the test. The laser circle scan and the laser cyclic-harmonic curve scan showed the ability to characterize the incident wavefronts of the S0 and A0 modes in the aluminum plate and the CFRP plate, respectively, followed by the laser hyperbolic curve scan. With the promising results obtained in the proposed method, the integration of the parametric curve scanning method into LUIS may provide a new approach to damage detection and useful information for ultrasonic algorithm design in NDE-SHM applications.

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“…The compressive sensing (CS) technique allows highdimensional signals to be reconstructed from a sparse basis representation, which improves the scan time of current wavefield imaging. [10][11][12] However, the signal reconstruction efficiency highly depends on dictionary quality, and there can be high computational or data collection demands to obtaining the "best" dictionary via supervised learning.…”

Section: Introductionmentioning

confidence: 99%

Laser Ultrasonic Imaging of Wavefield Spatial Gradients for Damage Detection

Chong¹,

Wu²,

Todd³

2021

Lecture Notes in Mechanical Engineering

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This paper describes a new damage visualization method to investigate and analyze propagating guided Lamb waves using analyses of wavefield spatial gradients. A laser ultrasonic interrogation system (LUIS) was used to create fullfield ultrasonic data measurements for ultrasonic wavefield imaging (UWI). The laser scanning process was performed based on both a raster scan and a circle scan. From the high-resolution wavefield data, a spatial gradient-based image processing technique was developed using gradient vectors to extract features sensitive to defects. Local impedance changes at the damaged area would result in a local distortion of the waveform which was captured and quantified by the variation of the gradient vectors in the scanning area as time evolves. Such variation was accumulated over time with a statistical threshold filter to generate a gradient-orientation map for damage visualization. The proposed algorithm was capable of producing distinctive damage patterns when tested experimentally on a 3-mm aluminum plate with multiple simultaneous simulated defects. Compared to conventional techniques like local wavenumber estimation, the generation of the accumulated orientation map involves no filtering process in the frequency or wavenumber domain, at the expense of more accurate shaping of the defect. A spatial covariance analysis was adopted to locate damage from the results as well as to evaluate the correlation between different kinds of defects. Combining the proposed approach with conventional laser ultrasonic imaging techniques enables a fast and robust damage identification and characterization process which requires lower computational burden and practical operation.

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Statistical partial wavefield imaging using Lamb wave signals

Cited by 24 publications

References 53 publications

Open Guided Waves: online platform for ultrasonic guided wave measurements

Open Guided Waves: online platform for ultrasonic guided wave measurements

Spatial ultrasonic wavefront characterization using a laser parametric curve scanning method

Laser Ultrasonic Imaging of Wavefield Spatial Gradients for Damage Detection

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