Results of the 2015 UT modeling benchmark obtained with models implemented in CIVA

Toullelan, Gwénaël; Raillon, R.; Chatillon, Sylvain; Dorval, Vincent; Darmon, Michel; Lonne, Sébastien

doi:10.1063/1.4940642

Cited by 7 publications

(3 citation statements)

References 3 publications

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“…Examples are given in [8]. They lead to a similar conclusion as here: the ray-based method tends to be more accurate than the plane-wave approximation.…”

Section: Comparison Of the Resultssupporting

confidence: 59%

Improved semi-analytical simulation of UT inspections using a ray-based decomposition of the incident fields

Dorval¹,

Leymarie²,

Chatillon³

2016

AIP Conference Proceedings

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Abstract. Semi-analytical models are often used for computationally efficient ultrasonic simulations. They typically apply plane-wave or quasi plane-wave approximations to the ultrasonic fields at the location of flaws in order to calculate diffraction coefficients. In favorable cases, the plane-wave approximations used for echo computations in the Civa software yield satisfying results. However, it can lead to inaccuracies in unfavorable cases, such as for wide probe apertures, outside of the focal region, or for beam-splitting or distortion due to irregular geometries. This communication presents an improved model, implemented in a development version of the software. The new approach describes the ultrasonic field as a sum of rays and applies the plane-wave approximation to each ray instead of the entire field. It significantly improves the accuracy of echo computations. However, it implies that the diffraction is calculated for each pair of incident and diffracted rays instead of being calculated only once: a specific algorithm has been developed in order to avoid a significant increase in computation times. Benefits of the new approach are illustrated by comparing its results and computation times to those of the former plane-wave model in several cases of interest. They are also compared to those of a coupled finite element model (Civa-Athena).

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“…Examples are given in [8]. They lead to a similar conclusion as here: the ray-based method tends to be more accurate than the plane-wave approximation.…”

Section: Comparison Of the Resultssupporting

confidence: 59%

Improved semi-analytical simulation of UT inspections using a ray-based decomposition of the incident fields

Dorval¹,

Leymarie²,

Chatillon³

2016

AIP Conference Proceedings

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“…In order to evaluate the Conoir and Norris (CN) model for concrete structures, one can study its response in terms of phase velocity and attenuation as a function of the longitudinal incident wave's frequency, and in comparison with the two FEM numerical tools: 2D CIVA FEM and 2D SPECFEM software. CIVA is a NDT/SHM simulation and analysis platform, including simulation tools for different NDT techniques, notably ultrasonic models intensively validated [15,16]. System models [17] based on the reciprocity principle have been devised to simulate the ultrasonic response of flaws for various NDT configurations [18].…”

Section: Evaluation Of 2d Elastic Homogenization Models For Concrete ...mentioning

confidence: 99%

2D Analytical Modelling for Ultrasonic Inspection of Concrete Structures: Effects of Scatterers Position Correlation

Khalid,

Darmon,

Chaix

2024

J. Phys.: Conf. Ser.

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Ultrasonic Non-Destructive Testing (NDT) simulation plays an important role in designing inspections of concrete structures. The concrete structural complexity (presence of different heterogeneities: aggregates, porosities, microcracks …) leads to dispersion and attenuation of the ultrasonic waves, which requires an accurate modelling of the waves scattered from heterogeneities. For that purpose, studying the mean coherent wave characterized by its attenuation and phase velocity is of great interest. Two major approaches (numerical or analytical) exist for modelling the coherent wave. Numerical methods are more efficient but still limited in the 3D case by their computation time. Therefore, semi-analytical homogenization methods are considered a practical solution for a fast 3D simulation. Nevertheless, they may encounter several limitations in estimating the attenuation in dense heterogeneous materials such as concrete. Our goal is to explain and handle these prediction errors. Since the scattered ultrasonic field depends strongly on the obstacles’ positions in concrete, a particular focus is put on the pair correlation function describing the radial distribution of scatterers’ positions around a fixed scatterer (mean concentration at a distance r from this scatterer). Existing homogenization models are employed for simulating coherent wave propagation in concrete use by simplification of a uniform distribution. In order to improve the analytical models, the effects of scatterers’ positions correlation are investigated. In the present work, we propose to evaluate precisely the existing homogenization model that is the most suitable for high scatterers concentration. A comparison between this model and a 2D finite element code under development in the CIVA NDT simulation software is presented.

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“…If inspection is carried out in the near or intermediate field, the approximation of the locally plane wave for the incident field can be withdrawn, as has been shown in the recent report on the new promising GTD-based NDT system model which uses each incident ray as an input of the flaw scattering model. 28 The proposed UTD model can be used to model scattered echoes from any locally plane flaw, since according to the GTD locality principle, a curved edge of the flaw contour can be approximated by the edge of the half-plane, which is tangent to it. In modelling specular reflections, the finite size of the flaw is routinely accounted for in the GE ray method: only the incident rays impacting on the finite flaw surface are reflected.…”

Section: Scattering Of a Plane Elastic Wave By A Half-plane Cracmentioning

confidence: 99%

The Uniform geometrical Theory of Diffraction for elastodynamics: Plane wave scattering from a half-plane

Djakou

Darmon

Fradkin³

et al. 2015

The Journal of the Acoustical Society of America

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Diffraction phenomena studied in electromagnetism, acoustics, and elastodynamics are often modeled using integrals, such as the well-known Sommerfeld integral. The far field asymptotic evaluation of such integrals obtained using the method of steepest descent leads to the classical Geometrical Theory of Diffraction (GTD). It is well known that the method of steepest descent is inapplicable when the integrand's stationary phase point coalesces with its pole, explaining why GTD fails in zones where edge diffracted waves interfere with incident or reflected waves. To overcome this drawback, the Uniform geometrical Theory of Diffraction (UTD) has been developed previously in electromagnetism, based on a ray theory, which is particularly easy to implement. In this paper, UTD is developed for the canonical elastodynamic problem of the scattering of a plane wave by a half-plane. UTD is then compared to another uniform extension of GTD, the Uniform Asymptotic Theory (UAT) of diffraction, based on a more cumbersome ray theory. A good agreement between the two methods is obtained in the far field.

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Results of the 2015 UT modeling benchmark obtained with models implemented in CIVA

Cited by 7 publications

References 3 publications

Improved semi-analytical simulation of UT inspections using a ray-based decomposition of the incident fields

Improved semi-analytical simulation of UT inspections using a ray-based decomposition of the incident fields

2D Analytical Modelling for Ultrasonic Inspection of Concrete Structures: Effects of Scatterers Position Correlation

The Uniform geometrical Theory of Diffraction for elastodynamics: Plane wave scattering from a half-plane

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