Modelling of corner echo ultrasonic inspection with bulk and creeping waves

Huet, G.; Darmon, Michel; Lhéemery, Alain; Mahaut, S.

doi:10.1007/978-3-540-89105-5_19

Cited by 9 publications

(7 citation statements)

References 7 publications

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“…The CIVA software platform for NDE simulation, developed at CEA/LIST, enables a complete simulation of TOFD inspections: indeed different semi-analytical models [8,11,12] have been integrated to model all the echoes observed in a TOFD configuration (head wave, flaw edges diffractions, back wall echo…). The developed model for head waves simulation is based on the asymptotic ray theory [3] which has also been used to improve the modeling of flaw corner echoes [13,14]. Nevertheless, the existing head wave simulation can only be applied for a planar specimen composed of an isotropic medium.…”

Section: Introductionmentioning

confidence: 99%

Modeling of ray paths of head waves on irregular interfaces in TOFD inspection for NDE

Ferrand¹,

Darmon²,

Chatillon³

et al. 2014

Ultrasonics

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The TOFD (Time of Flight Diffraction) technique is a classical ultrasonic inspection method used in ultrasonic non-destructive evaluation (NDE). This inspection technique is based on an arrangement of two probes of opposite beam directions and allows a precise positioning and a quantitative evaluation of the size of cracks contained in the inspected material thanks to their edges diffraction echoes. Among the typical phenomena arising for such an arrangement, head waves, which propagate along the specimen surface and are chronologically the first waves reaching the receiver, are notably observed. Head wave propagation on planar surfaces in TOFD configurations is well known. However, realistic inspection configurations often involve components with irregular surfaces, like steel excavated specimens. Surface irregularity is responsible for numerous effects on the scattering of bulk waves, causing the melting of surface and bulk mechanisms in the head wave propagation. In order to extend the classical ray approach on these complex cases, a generic algorithm of ray tracing between interface points (GIRT) has been designed. With respect to time of flight minimization (i.e. the Generalized Fermat's Principle), ray paths can be computed by GIRT for different natures of waves scattered by the complex surfaces or by flaws. The head wave fronts computed by GIRT are notably in good agreement with FEM simulated results. This algorithm, based on pure kinematic analysis of waves propagation, represents a first step in the future development of a complete ray theory for head waves simulation on irregular interfaces.

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Section: Introductionmentioning

confidence: 99%

Modeling of ray paths of head waves on irregular interfaces in TOFD inspection for NDE

Ferrand¹,

Darmon²,

Chatillon³

et al. 2014

Ultrasonics

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“…Even at high frequencies, truncating the integration interval to I is not helpful, because 6c T ð0Þ are accumulation points. Instead it is truncated to I d ¼½n À 1 ; n þ 1 , where n 6 1 ¼ 6c T ð0Þ7d 6 . To assure that both n st and n br lie inside I d , the offsets are chosen to be d 6 ¼ d minðjc T ð0Þ7n st j; jc T ð0Þ7n br jÞ: It has been established by trial and error that the optimal choice of d is 0.1: When d < 0:1 the results are the same but the code takes longer to run; when d > 0:1 the quality of results is inferior.…”

Section: A the Integration Intervalmentioning

confidence: 99%

“…Let I contain n p . If this pole lies outside I d the corresponding endpoint of I d is moved to n 6 1 ¼ 6c T ð0Þ 70:001dðc T ð0Þ7n p Þ, so that n p is absorbed into the redefined I d .I fn p lies too close to an accumulation point (c T ð0Þ7n p < 10 À10 ) but far from the stationary point (k T ½f T ðn p ÞÀf T ðn s tÞ < p), its contribution is negligible and I d is not redefined.…”

Section: Polesmentioning

confidence: 99%

“…GTD is used in radar technology, design of reflector antennas, and ultrasonic NDE (Non-Destructive Evaluation of industrial materials). [6][7][8] PTD (Physical Theory of Diffraction) is the theory that extends the classical KA using the exact description of edge diffracted waves. 2,3 In the high-frequency regime, when such a description is unknown the corrections to the Kirchhoff diffraction coefficients can be obtained using their GTD counterparts.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A semi-numerical model for near-critical angle scattering

Fradkin¹,

Darmon

Chatillon

et al. 2016

The Journal of the Acoustical Society of America

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Numerous phenomena in the fields of physics and mathematics as seemingly different as seismology, ultrasonics, crystallography, photonics, relativistic quantum mechanics, and analytical number theory are described by integrals with oscillating integrands that contain three coalescing criticalities, a branch point, stationary phase point, and pole as well as accumulation points at which the speed of integrand oscillation is infinite. Evaluating such integrals is a challenge addressed in this paper. A fast and efficient numerical scheme based on the regularized composite Simpson's rule is proposed, and its efficacy is demonstrated by revisiting the scattering of an elastic plane wave by a stress-free half-plane crack embedded in an isotropic and homogeneous solid. In this canonical problem, the head wave, edge diffracted wave, and reflected (or compensating) wave each can be viewed as a respective contribution of a branch point, stationary phase point, and pole. The proposed scheme allows for a description of the non-classical diffraction effects near the "critical" rays (rays that separate regions irradiated by the head waves from their respective shadow zones). The effects include the spikes present in diffraction coefficients at the critical angles in the far field as well as related interference ripples in the near field.

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“…As part of inspection qualification, they routinely perform computer simulation of relevant configurations. If necessary this can be done with commercial finite-element packages, but, when the speed of simulation is of essence, whenever possible, inspectors use packages such as CIVA [10], which utilize approximate tools for simulating radiation, propagation and scattering of ultrasonic pulses in solids. One such tool is the elastodynamic Kirchhoff approximation (KA) [4,13] that relies on the well-known free-space Green's tensor for a homogeneous and isotropic solid as well as the classical assumptions of geometrical elastodynamics (GE): these are satisfied by large scatterers with locally straight edges, when both the incident wave front and the scatterer surface are locally plane.…”

Section: Introductionmentioning

confidence: 99%

The Alternative Kirchhoff Approximation in Elastodynamics With Applications in Ultrasonic Nondestructive Testing

Fradkin¹,

Djakou²,

Prior

et al. 2020

ANZIAM J.

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The Kirchhoff approximation is widely used to describe the scatter of elastodynamic waves. It simulates the scattered field as the convolution of the free-space Green’s tensor with the geometrical elastodynamics approximation to the total field on the scatterer surface and, therefore, cannot be used to describe nongeometrical phenomena, such as head waves. The aim of this paper is to demonstrate that an alternative approximation, the convolution of the far-field asymptotics of the Lamb’s Green’s tensor with incident surface tractions, has no such limitation. This is done by simulating the scatter of a critical Gaussian beam of transverse motions from an infinite plane. The results are of interest in ultrasonic nondestructive testing.

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Modelling of corner echo ultrasonic inspection with bulk and creeping waves

Cited by 9 publications

References 7 publications

Modeling of ray paths of head waves on irregular interfaces in TOFD inspection for NDE

Modeling of ray paths of head waves on irregular interfaces in TOFD inspection for NDE

A semi-numerical model for near-critical angle scattering

The Alternative Kirchhoff Approximation in Elastodynamics With Applications in Ultrasonic Nondestructive Testing

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