Accurate depth measurement of small surface-breaking cracks using an ultrasonic array post-processing technique

Felice, Maria V.; Velichko, Alexander; Wilcox, Paul D.

doi:10.1016/j.ndteint.2014.08.004

Cited by 89 publications

(60 citation statements)

References 16 publications

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“…For the TFM images, with the smaller crack depth, the indication of the crack tip is closer to the indication of the crack root, as the energy of the tip diffraction is much weaker than the energy reflected by the root corner, the indication of the crack tip is much weaker than the root, which causes the tip to be masked by the root in the TFM image of the 1λ deep crack. The smallest crack that TFM can successfully reconstruct is about 2λ, which shows good consistency with other research focused on imaging small cracks [12]. The TFM algorithm shows excellent robustness to noise as the addition of the noise does not affect the TFM images.…”

Section: Cracksupporting

confidence: 80%

“…The backwall of the object can be regarded as a strong reflector that would bring a strong specular reflection. Conventionally, this problem is solved by detecting the crack at an oblique incident angle (for example θ test = 45 • ), the resulting measured signals will only contain the tip diffraction and the echoes from the root corner since the specular backwall reflection will not be measured by the array [12]. However, with longer propagation distance there will be greater attenuation, reducing signal-to-noise, and similarly coherent noise from grain scattering will also be worse for longer path lengths.…”

Section: A Imaging For Surface-breaking Cracksmentioning

confidence: 99%

“…In response, Felice et al [11] developed the Half-Skip Total Focusing Method (HSTFM) to measure the depth of the surface-breaking crack which is near the backwall. The results showed that the HSTFM has the ability to size a 1.5 wavelength surface-breaking crack that is impossible to be measured through the conventional TFM, however, the HSTFM still had a poor accuracy for the cracks smaller than 1.5 wavelength [12]. As the TFM and the HSTFM is based on the weak scattering approximation (e.g., the Born approximation), there is a resolution limit called the Rayleigh limit (0.5 wavelength) that will limit the application of these methods in high resolution imaging [13].…”

Section: Introductionmentioning

confidence: 99%

“…To solve this problem, we have proposed a method that extracts the scattered field from the measured data captured on a component contained the defect. In some cases [12] the removal of the specular component is achieved by angling the incoming beam such that the specular reflection does not return to the array. The issue is that this generally requires the use of wedges, restricts the illumination angle and makes longer path lengths, increasing attenuation, and therefore this approach is not pursued in this paper.…”

Section: Introductionmentioning

confidence: 99%

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The Application of the Factorization Method to the Subsurface Imaging of Surface-Breaking Cracks

Zhang

Huthwaite

Lowe

2018

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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Abstract-A common location for cracks to appear is at the surface of a component; at the near surface, many nondestructive evaluation (NDE) techniques are available to inspect for these, but at the far surface this is much more challenging. Ultrasonic imaging is proposed to enable far surface defect detection, location and characterisation. One specific challenge here is the presence of a strong reflection from the backwall, which can often mask the relatively small response from a defect. In this paper, the Factorization Method (FM) is explored for the application of subsurface imaging of the surface-breaking cracks. In this application, the component has two parallel surfaces, the crack is initiated from the far side and the phased array is attached on the near side. Ideally, the pure scattered field from a defect is needed for the correct estimation of the scatterer through the FM algorithm. However, the presence of the backwall will introduce a strong specular reflection into the measured data which should be removed before applying the FM algorithm. A novel subtraction method was developed to remove the backwall reflection. The performance of the FM algorithm and this subtraction method were tested with the simulated and experimental data. The experimental results showed a good consistency with the simulated results. It is shown that the FM algorithm can generate high quality images to provide a good detection of the crack and an accurate sizing of the crack length. The subtraction method was able to provide a good backwall reflection removal in the case of small cracks (1-3 wavelengths).

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Section: Cracksupporting

confidence: 80%

Section: A Imaging For Surface-breaking Cracksmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The Application of the Factorization Method to the Subsurface Imaging of Surface-Breaking Cracks

Zhang

Huthwaite

Lowe

2018

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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“…To this end, researchers have come up with solutions. Felice et al [8] used ultrasonic-array total focusing technology to measure the depth of surface cracks (<1 mm). Hu et al [9] reported a stereoscopic fluorescence profilometry to measure the thickness and morphology of transparent films.…”

Section: Introductionmentioning

confidence: 99%

Efficient Shape Estimation of Transparent Microdefects with Manifold Learning and Regression on a Set of Saturated Images

Deng¹,

Pan²,

Zhong³

2020

Applied Sciences

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Featured Application: The paper provides a convenient method to determine if a suspected microdefect of polarizer film is real. This is useful for manufacturing of diverse flexible/ transparent thin-film. Abstract:In the industry of polymer film products such as polarizers, measuring the three-dimensional (3D) contour of the transparent microdefects, the most common defects, can crucially affect what further treatment should be taken. In this paper, we propose an efficient method for estimating the 3D shape of defects based on regression by converting the problem of direct measurement into an estimation problem using two-dimensional imaging. The basic idea involves acquiring structured-light saturated imaging data on transparent microdefects; integrating confocal microscopy measurement data to create a labeled data set, on which dimensionality reduction is performed; using support vector regression on a low-dimensional small-set space to establish the relationship between the saturated image and defects' 3D attributes; and predicting the shape of new defect samples by applying the learned relationship to their saturated images. In the discriminant subspace, the manifold of saturated images can clearly show the changing attributes of defects' 3D shape, such as depth and width. The experimental results show that the mean relative error (MRE) of the defect depth is 3.64% and the MRE of the defect width is 1.96%. The estimation time consumed in the Matlab platform is less than 0.01 s. Compared with precision measuring instruments such as confocal microscopes, our estimation method greatly improves the efficiency of quality control and meets the accuracy requirement of automated defect identification. It is therefore suitable for complete inspection of products.

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An ultrasonic wave‐based framework for imaging internal cracks in concrete

Kuchipudi

Ghosh

2022

Structural Contr & Hlth

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Nondestructive detection and sizing of internal cracks initiated in reinforced concrete have been critical problems. Geometric characterization of internal cracks and delaminations contributes to predicting their propagation path and failure pattern followed by structural prognostics. There have been limited studies on quantitative detection and characterization of vertical cracks in concrete using wave-based NDE techniques. This study focuses on solving the problem of imaging deep internal crack planes in the concrete medium by leveraging the ultrasonic shear horizontal (SH) waves from a transducer array. Postprocessing the array full matrix capture (FMC) data with both total focusing method (TFM) and plane wave imaging (PWI) reveals their efficiency in mapping planar defects inclined between 0 and 60 . However, their performance on vertical/near-vertical defects is found to be inferior with imaging limited to the tip of the defect planes. Further, half-skip modes of wave dispersion have been adopted in addition to the directly scattered pulses for imaging the vertical and near-vertical cracks. We propose an imaging framework based on the outcomes of our investigation on the best suitable methodology to detect and map planar defects like cracks inclined in the range of 0-90 . Statistical quantification of defect inclinations from the reconstructed images is compared to the ground-truth orientations, and they are found to be 94%-99% accurate. Besides accuracy, the computational efficiency of the proposed techniques makes them desirable and reliable for quick on-site inspections on built infrastructure.full matrix capture (FMC), total focusing method (TFM), half-skip total focusing method (HSTFM), plane wave imaging (PWI), shear horizontal (SH) waves, ultrasonic array, vertical cracks | INTRODUCTIONInternal cracks in reinforced concrete are a result of various factors including thermal, mechanical, and environmental deterioration. Cracking affects the performance of structural concrete at different stages in its lifecycle. Diagnosis of such defects is followed by retrofitting at early stages to mitigate the failure of structures. The non-homogeneity and highly attenuating nature of concrete medium poses a challenge for the nondestructive community to evaluate structures for thin underlying cracks.

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Accurate depth measurement of small surface-breaking cracks using an ultrasonic array post-processing technique

Cited by 89 publications

References 16 publications

The Application of the Factorization Method to the Subsurface Imaging of Surface-Breaking Cracks

The Application of the Factorization Method to the Subsurface Imaging of Surface-Breaking Cracks

Efficient Shape Estimation of Transparent Microdefects with Manifold Learning and Regression on a Set of Saturated Images

An ultrasonic wave‐based framework for imaging internal cracks in concrete

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