Ultrasonic crack evaluation by phase coherence processing and TFM and its application to online monitoring in fatigue tests

Camacho, J.; Atehortua, D.; Cruza, Jorge F.; Brizuela, José; Ealo, Joao L.

doi:10.1016/j.ndteint.2017.10.007

Cited by 39 publications

(15 citation statements)

References 23 publications

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“…Thus, in this section, an algorithm derived from TFM is presented; it relies only on the coherent summation of signal instantaneous phase [ 17 ]. This algorithm has been considered in the past as a weighting factor for amplitude-based images in order to reduce artefacts [ 18 ].…”

Section: Methodsmentioning

confidence: 99%

“…Additionally, since defect sizing currently relies on calibrated amplitude, direct phase-based image reconstruction allows a different approach, in which calibration is no longer a requirement, as amplitude information is simply disregarded. It appears that in the case of narrow defects, tips are particularly well represented in such images, which allow accurate sizing and localization of reflectors [ 18 ].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Towards an Alternative to Time of Flight Diffraction Using Instantaneous Phase Coherence Imaging for Characterization of Crack-Like Defects

Gauthier

Painchaud-April²,

Duff³

et al. 2021

Sensors

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Time of flight diffraction (TOFD) is considered a reliable non-destructive testing method for the inspection of welds using a pair of single-element probes. On the other hand, ultrasonic phased array imaging has been continuously developed over the last couple of decades, and now features powerful algorithms, such as the total focusing method (TFM) and its multi-view approach to rendering detailed images of inspected parts. This article focuses on a different implementation of the TFM algorithm, relying on the coherent summation of the instantaneous signal phase. This approach presents a wide range of benefits, such as removing the need for calibration, and is highly sensitive to defect tips. This study compares the sizing and localization capabilities of the proposed method with the well-known TOFD. Both instantaneous phase algorithm and TOFD do not take advantage of the signal amplitude. Experimental tests were performed on a ¾″-thick steel sample with crack-like defects at different angles. Phase-based imaging techniques showed similar characterization capabilities as the standard TOFD method. However, the proposed method adds the benefit of generating an easy-to-interpret image that can help in localizing the defect. These results pave the way for a new characterization approach, especially in the field of automated ultrasonic testing (AUT).

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Towards an Alternative to Time of Flight Diffraction Using Instantaneous Phase Coherence Imaging for Characterization of Crack-Like Defects

Gauthier

Painchaud-April²,

Duff³

et al. 2021

Sensors

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“…For example, the full extent of cracks can be imaged by focusing the specular reflections of different wave mode combinations, known in the NDT community as multi-mode imaging [8], or multi-view. This technique has been studied by different research groups in order to minimise artefacts in realistic configurations [9], [10], and to estimate the length and orientation of cracks [11], [12]. However, prior knowledge of the position and shape of the defect is sometimes needed to choose the appropriate mode combination, especially in presence of complex interfaces.…”

Section: Introductionmentioning

confidence: 99%

Optimal Extraction of Ultrasonic Scattering Features in Coarse Grained Materials

Villaverde

Croxford

Velichko

2021

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

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Ultrasonic array imaging is used in non-destructive testing for detection and characterisation of defects. The scattering behaviour of any feature can be described by a matrix of scattering coefficients, called the scattering matrix. This information is used for characterisation, and contrary to imagebased analysis, the scattering matrix allows characterisation of defects at the subwavelength scale. However, the defect scattering coefficients are in practice contaminated by other nearby scatterers or significant structural noise. In this context, an optimal procedure to extract scattering features from a selected region of interest in a beamformed image is here investigated. This work proposes two main strategies to isolate a target scatterer in order to recover exclusively the time responses of the desired scatterer.In this paper such strategies are implemented in delay-and-sum and frequency-wavenumber forms, and optimised to maximise the extraction rate. An experimental case in a polycrystalline material shows that the suggested procedures provide a rich frequency spectrum of the scattering matrix and are readily suited to minimise the effects of surrounding scattering noise. In doing so, the ability to deploy imaging methods that rely on the scattering matrix is enabled.

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“…In particular, TFM is based on the full matrix capture (FMC), which contains every emitting–receiving combination in post-processing imaging. Because it provides the best resolution and a larger dynamic range, TFM is usually considered the “gold standard” in the NDT&E field [ 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

Space Optimized Plane Wave Imaging for Fast Ultrasonic Inspection with Small Active Aperture: Simulation and Experiment

Sui

Huang

et al. 2020

Sensors

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Plane wave imaging (PWI) is attracting more attention in industrial nondestructive testing and evaluation (NDT&E). To further improve imaging quality and reduce reconstruction time in ultrasonic imaging with a limited active aperture, an optimized PWI algorithm was proposed for rapid ultrasonic inspection, with the comparison of the total focusing method (TFM). The effective area of plane waves and the space weighting factor were defined in order to balance the amplitude of the imaging area. Experiments were carried out to contrast the image quality, with great agreement to the simulation results. Compared with TFM imaging, the space-optimized PWI algorithm demonstrated a wider dynamic detection range and a higher defects amplitude, where the maximum defect amplitude attenuation declined by 6.7 dB and average attenuation on 12 defects decreased by 3.1 dB. In addition, the effects of plane wave numbers on attenuation and reconstruction time were focused on, achieving more than 10 times reduction of reconstruction times over TFM.

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Ultrasonic crack evaluation by phase coherence processing and TFM and its application to online monitoring in fatigue tests

Cited by 39 publications

References 23 publications

Towards an Alternative to Time of Flight Diffraction Using Instantaneous Phase Coherence Imaging for Characterization of Crack-Like Defects

Towards an Alternative to Time of Flight Diffraction Using Instantaneous Phase Coherence Imaging for Characterization of Crack-Like Defects

Optimal Extraction of Ultrasonic Scattering Features in Coarse Grained Materials

Space Optimized Plane Wave Imaging for Fast Ultrasonic Inspection with Small Active Aperture: Simulation and Experiment

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