Acoustic characterization of void distributions across carbon-fiber composite layers

Tayong, Rostand; Smith, Robert A.; Pinfield, Valerie J.

doi:10.1063/1.4940593

Cited by 4 publications

(2 citation statements)

References 24 publications

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“…Frequency dependence of ultrasonic attenuation does give a handle on size distribution but this has not been used successfully for porosity in an inhomogeneous anisotropic solid [5]. Recent attempts to decompose the frequency-dependent pulse-echo response into separate contributions from porosity and thickening of resin layers by [6], and [7], [8] have had some success in producing a 3D map of local porosity. Whilst these methods have shown potential, they still need further work to improve the decomposition process.…”

Section: Introductionmentioning

confidence: 99%

A parametric study of segmentation thresholds for X-ray CT porosity characterisation in composite materials

Tretiak

Smith

2019

Composites Part A: Applied Science and Manufacturing

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Porosity in composites is a critical manufacturing defect that leads to a reduction of mechanical performance. Non-destructive testing (NDT) techniques are used to inspect composites after manufacture to identify defects and to help assess their impact on mechanical performance. Micro X-ray computed tomography is a promising NDT technique which provides information about pore location, size and morphology. To identify and characterise voids, an image 'segmentation' must be applied to the full CT dataset, which is simply a rule-based decision about whether a voxel is inside a pore or not. This work uses a simple model to analyse and compare the effectiveness of previously accepted threshold methods for segmentation across a range of material and porosity parameters. A new CT-segmentation thresholding method is proposed and evaluated for characterising voids in a wider range of composites.The sources of uncertainties are investigated and recommendations are made to minimise these uncertainties.

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Section: Introductionmentioning

confidence: 99%

A parametric study of segmentation thresholds for X-ray CT porosity characterisation in composite materials

Tretiak

Smith

2019

Composites Part A: Applied Science and Manufacturing

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“…of the backscattered signal by means of experimental testing. Apart from those experimental methods, numerical methods [9,10,11,12,13] have also been widely used for acoustic characterization.…”

Section: Introductionmentioning

confidence: 99%

Ultrasonic Inspection of Localized Defects in Low-Porosity CFRP

Feng

Zhou

Zeng

et al. 2019

Sensors

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A preliminary backscattered signal model of carbon-fiber-reinforced plastic (CFRP) laminate was established. The backscattered signal model was composed of three sub models, which were concerned with structural signal, scattering signal, and non-acoustic noise. Resonance in structural signal and echoes excited by defects (porosity and rich-resin) were studied. The results showed that: resonance would occur when there was sufficient bandwidth; when the CFRP laminate contained voids, the center frequency of the backscattered signal decreased; and the localized defects, including rich-resin and localized porosity, tended to generate apparent echoes where they located. A simplified backscattered signal model was subsequently put forward, showing certain potential in revealing time-frequency properties of backscattered signals. The newly proposed variational mode decomposition was used for defect modes extraction, successfully avoiding the mode mixing and false modes which easily exist in empirical mode decomposition. Subsequently, the generalized Stockwell transform was adopted for the defects localization. The simulation and experiment denoted the coincidence between the backscattered signal model and the experimental signal, and showed the effectiveness of variational mode decomposition and generalized Stockwell transform in localized defects detection.

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Suppression of front and back surface reflections in ultrasonic analytic-signal responses from composites

Zilidou

Smith²,

Wilcox³

2022

Ultrasonics

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Acoustic characterization of void distributions across carbon-fiber composite layers

Cited by 4 publications

References 24 publications

A parametric study of segmentation thresholds for X-ray CT porosity characterisation in composite materials

A parametric study of segmentation thresholds for X-ray CT porosity characterisation in composite materials

Ultrasonic Inspection of Localized Defects in Low-Porosity CFRP

Suppression of front and back surface reflections in ultrasonic analytic-signal responses from composites

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