Ultrasonic Examination of an Austenitic Weld: Illustration of the Disturbances of the Ultrasonic Beam

Chassignole, Bertrand; Dupond, O.; Doudet, Ludovic; Duwig, V.; Etchegaray, N.

doi:10.1063/1.3114189

Cited by 9 publications

(6 citation statements)

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“…propagation in coarse-grained materials such as CASS. 10,[13][14][15][16][17][18][19][20] Phenomena that have been documented include beam deviation or skew, [6][7][8][9]18 phase distortion of the acoustic wave front, 10,21,22 and attenuation. 8,23 A detailed discussion of acoustic wave behavior in coarse-grained anisotropic materials, particularly CASS, along with a comprehensive bibliographical listing of relevant literature, is presented in Ramuhalli et al ( †) The phenomena discussed above have a deleterious effect on the ultrasonic signal from CASS specimens.…”

Section: Ultrasonic Wave Behavior In Cassmentioning

confidence: 99%

Evaluation of signal processing tools for improving phased array ultrasonic weld inspection

et al. 2011

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Cast austenitic stainless steel (CASS) that was commonly used in U.S. nuclear power plants is a coarse-grained, elastically anisotropic material. In recent years, low-frequency phased-array ultrasound has emerged as a leading candidate for the inspection of welds in CASS piping, due to the relatively lower interference in the measured signal from ultrasonic backscatter. However, adverse phenomena (such as scattering from the coarse-grained microstructure, and beam redirection and partitioning due to the elastically anisotropic nature of the material) result in measurements with a low signal-to-noise ratio (SNR), and increased difficulty in discriminating between signals from flaws and signals from benign geometric factors. There is therefore a need for advanced signal processing tools to improve the SNR and enable rapid analysis and classification of measurements. This paper discusses recent efforts at PNNL towards the development and evaluation of a number of signal processing algorithms for this purpose. Among the algorithms being evaluated for improving the SNR (and, consequently, the ability to discriminate between flaw signals and non-flaw signals) are wavelets and other time-frequency distributions, empirical mode decompositions, and split-spectrum processing techniques. A range of pattern-recognition algorithms, including neural networks, are also being evaluated for their ability to successfully classify measurements into two or more classes. Experimental data obtained from the inspection of a number of welds in CASS components are being used in this evaluation.

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Section: Ultrasonic Wave Behavior In Cassmentioning

confidence: 99%

Evaluation of signal processing tools for improving phased array ultrasonic weld inspection

et al. 2011

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“…Indeed, some disturbances of the beam, such as splitting and skewing [1], can be observed on experimental echoes. It has been highlighted that these disruptions are due to the anisotropic and inhomogeneous polycrystalline structure of the weld [2].…”

Section: Context and Objectivesmentioning

confidence: 99%

Paraxial ray-tracing approach for the simulation of ultrasonic inspection of welds

Gardahaut

Jezzine

Cassereau

2014

AIP Conference Proceedings

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On-site inspection of bimetallic or austenitic welds can be very difficult to interpret owing to their internal structures. Skewing and splitting of the ultrasonic beam may occur due to the anisotropic and inhomogeneous properties of the welding material. In this paper, we present a ray-based method to simulate the propagation of ultrasonic waves in such structures. The formalism is based on dynamic ray tracing system in Cartesian coordinates along a reference ray. Standard ray tracing consists in the solution of a system of linear ordinary differential equations of the first order and is used to determine the trajectory of the ray. Likewise, dynamic ray tracing (DRT) also called paraxial ray tracing consists in the solution of an additional system of linear ordinary differential equations along the ray allowing paraxial quantities to be computed. It is used to evaluate the geometrical spreading and amplitude along the ray and in its vicinity. DRT is applied on a smooth representation of the elastic properties of the weld obtained thanks to an image processing technique applied on a macrograph of the weld. Simulation results are presented and compared to finite elements and experimental results.

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“…Contact and immersed transducers are implemented. Calculations can be performed for all type of structures, especially anisotropic and heterogeneous structures [8] and take into account wave attenuation due to grain scattering [9]. The beam propagation and beam to defect interactions are calculated with all conversion modes.…”

Section: Athena Finite Element Model Characteristicsmentioning

confidence: 99%

Influence of Stress Corrosion Crack Morphology on Ultrasonic Examination Performances

Dupond¹,

Duwig²,

Fouquet³

2009

AIP Conference Proceedings

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Stress Corrosion Cracking represents a potential damage for several components in PWR. For this reason, NDE of stress corrosion cracks corresponds to an important stake for Electricité de France (EDF) both for the availability and for the safety of plants. SCC crack encountered for Ni-based components in primary coolant medium usually presents an intergranular propagation. The degradation mechanism then induces morphological specificities of the defect, such as rugosity or branched characteristics. Compared with fatigue cracks, SCC morphology may then have an effect on NDE performances, both in terms of detection and characterisation of the defect. The goal of this paper is to evaluate the influence of the stress corrosion crack morphology on the ultrasonic inspection. The study mixes an experimental approach conducted on artificial flawssupposed to represent the morphologic features of SCC cracks-and a modelling approach with the 2D finite elements code ATHENA 2D developed by EDF, the semi-analytical code CIVA developed by CEA/LIST and an hybrid code coupling semi-analytical and finite elements code, developed by EDF and CEA. By comparison of experimental and modelling results, the beam-defect interaction in models is validated for complex 2D defects. The interest of modelling is then illustrated with the analysis of specific ultrasonic response observed experimentally for different defects and reproduced with modelling.

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Ultrasonic Examination of an Austenitic Weld: Illustration of the Disturbances of the Ultrasonic Beam

Cited by 9 publications

References 0 publications

Evaluation of signal processing tools for improving phased array ultrasonic weld inspection

Evaluation of signal processing tools for improving phased array ultrasonic weld inspection

Paraxial ray-tracing approach for the simulation of ultrasonic inspection of welds

Influence of Stress Corrosion Crack Morphology on Ultrasonic Examination Performances

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