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17 results on '"Theodoros Theodoulidis"'

1. Computation of eigenvalues and eigenfunctions in the solution of Eddy current problems

Author

Theodoros Theodoulidis, Anastassios Skarlatos, Grzegorz Tytko, University of Western Macedonia [Kozani] (UoWM), Laboratoire de Simulation, Modélisation et Analyse (LSMA-LIST), Département d'instrumentation Numérique (DIN (CEA-LIST)), Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, and Silesian University of Technology

Subjects
Electrical and Electronic Engineering, Biochemistry, Instrumentation, Atomic and Molecular Physics, and Optics, [MATH.MATH-NA]Mathematics [math]/Numerical Analysis [math.NA], Analytical Chemistry, nondestructive testing, eddy current testing, eigenvalues and eigenfunctions, complex roots
Abstract

International audience; The solution of the eigenvalue problem in bounded domains with planar and cylindrical stratification is a necessary preliminary task for the construction of modal solutions to canonical problems with discontinuities. The computation of the complex eigenvalue spectrum must be very accurate since losing or misplacing one of the thereto linked modes will have an important impact on the field solution. The approach followed in a number of previous works is to construct the corresponding transcendental equation and locate its roots in the complex plane using the Newton–Raphson method or Cauchy-integral-based techniques. Nevertheless, this approach is cumbersome, and its numerical stability decreases dramatically with the number of layers. An alternative, approach consists in the numerical evaluation of the matrix eigenvalues for the weak formulation for the respective 1D Sturm–Liouville problem using linear algebra tools. An arbitrary number of layers can thus be easily and robustly treated, with continuous material gradients being a limiting case. Although this approach is often used in high frequency studies involving wave propagation, this is the first time that has been used for the induction problem arising in an eddy current inspection situation. The developed method is implemented in Matlab and is used to deal with the following problems: magnetic material with a hole, a magnetic cylinder, and a magnetic ring. In all the conducted tests, the results are obtained in a very short time, without missing a single eigenvalue.

Published
2023

2. Study of the non-linear eddy-current response in a ferromagnetic plate: Theoretical analysis for the 2D case

Author

Anastassios Skarlatos, Theodoros Theodoulidis, Département Imagerie et Simulation pour le Contrôle (DISC), Laboratoire d'Intégration des Systèmes et des Technologies (LIST), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, and Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA))

Subjects
FOS: Physical sciences, 02 engineering and technology, Physics - Classical Physics, 01 natural sciences, law.invention, Harmonic excitation, law, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Eddy current, General Materials Science, Experimental work, Fourier domain, ComputingMilieux_MISCELLANEOUS, 010302 applied physics, Physics, [PHYS]Physics [physics], Total harmonic distortion, Mechanical Engineering, 020208 electrical & electronic engineering, Mathematical analysis, Classical Physics (physics.class-ph), Eigenfunction, Condensed Matter Physics, Nonlinear system, Ferromagnetism
Abstract

The non-linear induction problem in an infinite ferromagnetic pate is studied theoretically by means of the truncated region eigenfunction expansion (TREE) for the 2D case. The non-linear formulation is linearised using a fixed-point iterative scheme, and the solution of the resulting linear problem is constructed in the Fourier domain following the TREE formalism. The calculation is carried out for the steady-state response under harmonic excitation and the harmonic distortion is derived from the obtained spectrum. This article is meant to be the theoretical part of a study, which will be complemented by the corresponding experimental work in a future communication.

Published
2018

3. ECT-signal calculation of cracks near fastener holes using an integral equation formalism with dedicated Green’s kernel

Author

Theodoros Theodoulidis, Dominique Lesselier, Konstantinos Pipis, Anastassios Skarlatos, Laboratoire d'Intégration des Systèmes et des Technologies (LIST), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), MEANDER, Department of Mechanical Engineering, University of Western Macedonia [Kozani] (UoWM)-University of Western Macedonia [Kozani] (UoWM), Laboratoire des signaux et systèmes (L2S), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA))

Subjects
business.product_category, Borehole, 02 engineering and technology, Green’s function, 01 natural sciences, Fastener, TREE method, Green S, Volume integral, chemistry.chemical_compound, [MATH.MATH-MP]Mathematics [math]/Mathematical Physics [math-ph], Eddy-current testing, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, eddy-current testing, 010302 applied physics, Physics, Holstein–Herring method, 020208 electrical & electronic engineering, Mathematical analysis, surface integral method, Eigenfunction, Physics::Classical Physics, Integral equation, Electronic, Optical and Magnetic Materials, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, chemistry, business
Abstract

International audience; Simulation of flaw detection by eddy-current testing requires the calculation of the eddy-current signal due to the presence of the flaw. In this paper, the surface integral method (SIM) is applied for the calculation of the crack signal in work-pieces composed of a conducting plate with a borehole. The adopted approach makes use of a Green’s operator that takes into account the effect of the borehole, thus the integral formalism is restricted to the crack surface only. The truncated region eigenfunction expansion (TREE) method is followed for the construction of the Green’s operator. Comparisons of the computed crack signal with numerical simulations carried out using a hybrid VIM-SIM approach and experimental results show excellent agreement.

Published
2016

4. Impedance of an induction coil accounting for the end-effect in eddy current inspection of steam generator tubes

Author

Konstantinos Pipis, Anastassios Skarlatos, Theodoros Theodoulidis, Dominique Lesselier, Département Imagerie et Simulation pour le Contrôle (DISC), Laboratoire d'Intégration des Systèmes et des Technologies (LIST), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, MEANDER, Department of Mechanical Engineering, University of Western Macedonia [Kozani] (UoWM)-University of Western Macedonia [Kozani] (UoWM), Laboratoire des signaux et systèmes (L2S), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), N.Yusa, T. Uchimoto, H. Kikuchi, and Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA))

Subjects
[SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, eddy-current inspection, [MATH.MATH-MP]Mathematics [math]/Mathematical Physics [math-ph], tube, Surface Integral Method, TREE method
Abstract

International audience; A fast model for the eddy-current signal calculation of thin cracks at the vicinity of a conducting tube edge is presented. The model is based on the surface integral equation formalism using a dedicated Green’s function. The approach followed for the construction of the Green’s kernel and the primary field is the Truncated Region Eigenfunction Expansion (TREE) method.

Published
2015

5. Calculation of the Eddy-Current Flow Around a Cylindrical Through-Hole in a Finite-Thickness Plate

Author

Anastassios Skarlatos, Theodoros Theodoulidis, Département Imagerie et Simulation pour le Contrôle (DISC), Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, MEANDER, Department of Mechanical Engineering, University of Western Macedonia [Kozani] (UoWM)-University of Western Macedonia [Kozani] (UoWM), and Laboratoire d'Intégration des Systèmes et des Technologies (LIST)

Subjects
010302 applied physics, Physics, eddy-current testing (ECT), fastener inspection, Mechanics, 01 natural sciences, Integral equation, Electronic, Optical and Magnetic Materials, law.invention, mode matching, Superposition principle, [SPI]Engineering Sciences [physics], Planar, law, 0103 physical sciences, Eddy current, Boundary value problem, impedance calculation, Electrical and Electronic Engineering, Domain truncation, 010301 acoustics, Finite thickness, Electrical conductor, Vector potential
Abstract

International audience; A semianalytical solution to the eddy-current induction problem in a conducting, nonmagnetic plate near a cylindrical through-holeis derived by means of the second-order vector potential and the domain truncation technique. The construction of a solution, which simultaneously satisfies the field continuity across the cylindrical surface of the hole and the planar interfaces of the plate, proves to be a very challenging problem, and thus, a special superposition of partial subsolutions is proposed. The presented solution is part of a more general development aiming at the calculation of the probe interaction with material flaws located in the vicinity of the hole by means of the integral equation formalism. These tasks will be the subject of a future paper. The comparison of the semianalytical results against both finite-element simulations as well as experimental data demonstrates excellent agreement.

Published
2015

6. Semi-analytical calculation of the low-frequency electromagnetic scattering from a near-surface spherical inclusion in a conducting half-space

Author

Theodoros Theodoulidis, Anastassios Skarlatos, Département Imagerie et Simulation pour le Contrôle (DISC), Laboratoire d'Intégration des Systèmes et des Technologies (LIST), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Department of Mechanical Engineering, University of Western Macedonia [Kozani] (UoWM), CIVAMONT collaboration, and Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA))

Subjects
domain truncation, Primary field, General Mathematics, domain, General Physics and Astronomy, Geometry, 01 natural sciences, law.invention, 010309 optics, law, 0103 physical sciences, Eddy current, applied mathematics, [INFO]Computer Science [cs], [MATH]Mathematics [math], eddy-currents, Parametric statistics, Mathematics, mathematical modelling Keywords: low-frequency scattering, 010302 applied physics, Subject Areas: electromagnetism, Scattering, mode-matching, General Engineering, non-destructive testing, Half-space, Computational physics, Modal, spherical inclusions, Electromagnetic coil, Excited state, low-frequency scattering
Abstract

International audience; The low-frequency electromagnetic scattering problem of a near-surface hollow spherical inclusion is solved by means of a modal approach. The primary field is excited using a current-carrying coil. The presented solution addresses the full coupling between the two interfaces of the geometry in a rigorous way. There is a direct physical interpretation of the different occurring terms in the formal solution, which provides a deeper understanding of the underlying phenomena. The calculation is very fast, which makes the proposed model suitable for use with parametric inversion algorithms.

Published
2014

7. Semi-analytical solution to the 2014 eddy current benchmark problem

Author

Christophe Reboud, Charitini Voulgaraki, Theodoros Theodoulidis, N. Poulakis, Roberto Miorelli, Laboratoire de Simulation et de Modélisation Électromagnetique (LSME), Département Imagerie et Simulation pour le Contrôle (DISC), Laboratoire d'Intégration des Systèmes et des Technologies (LIST), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Laboratoire d'Intégration des Systèmes et des Technologies (LIST), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Department of Mechanical Engineering, University of Western Macedonia [Kozani] (UoWM), Technological Educational Institute of Western Macedonia [Grevena] (TEIWM), Chimenti, DE and Bond, LJ, Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA))

Subjects
[PHYS]Physics [physics], Engineering, business.industry, Computation, Reference data (financial markets), Experimental data, 020206 networking & telecommunications, 02 engineering and technology, law.invention, [SPI]Engineering Sciences [physics], law, Eddy-current testing, 0202 electrical engineering, electronic engineering, information engineering, Benchmark (computing), Electronic engineering, Eddy current, 020201 artificial intelligence & image processing, Hall effect sensor, Sensitivity (control systems), business, Algorithm
Abstract

41st Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE), Boise, ID, JUL 20-25, 2014; International audience; This work proposes a solution to the 2014 eddy current testing benchmark, published by the WFNDEC and proposed by the authors. The aim of this benchmark is to provide reference data for eddy current testing configurations involving magnetic sensors here Hall sensors as receivers, as they present some advantages in terms of resolution and sensitivity. After a presentation of the benchmark cases, the theoretical approach used to solve the equivalent electromagnetic problem is detailed and a alternative computation of eddy current signals is proposed. Then, simulations are quantitatively compared to experimental data in each case and the results are discussed.

Published
2014

8. Eddy-current inspection modelling of a thin crack emanating from a borehole in a conducting plate

Author

Konstantinos Pipis, Anastassios Skarlatos, Theodoros Theodoulidis, Dominique Lesselier, Département Imagerie et Simulation pour le Contrôle (DISC), Laboratoire d'Intégration des Systèmes et des Technologies (LIST), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, MEANDER, Department of Mechanical Engineering, University of Western Macedonia [Kozani] (UoWM)-University of Western Macedonia [Kozani] (UoWM), Laboratoire des signaux et systèmes (L2S), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Lesselier, Dominique, and Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA))

Subjects
thin crack, [SPI]Engineering Sciences [physics], [SPI] Engineering Sciences [physics], Truncated Region Eigenfunction Exapnsion method, Eddy Current NDT, Physics::Geophysics
Abstract

International audience; A fast model for the eddy-current signal calculation of thin cracks emanating from a borehole in a conducting plate is presented. The model is based on the surface integral equation formalism using a dedicated Green’s function, which takes into account the effect of the borehole. The approach followed for the construction of the Green’s kernel and the primary field is the Truncated Region Eigenfunction Exapnsion (TREE) method

Published
2014

9. Coupled approach VIM-BEM for efficient modeling of ECT signal due to narrow cracks and volumetric flaws in planar layered media

Author

Christophe Reboud, Theodoros Theodoulidis, John Martinos, Roberto Miorelli, N. Poulakis, Dominique Lesselier, Département Imagerie et Simulation pour le Contrôle (DISC), Laboratoire d'Intégration des Systèmes et des Technologies (LIST), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, MEANDER, Department of Mechanical Engineering, University of Western Macedonia [Kozani] (UoWM)-University of Western Macedonia [Kozani] (UoWM), University of Western Macedonia [Kozani] (UoWM), DRE - Département de Recherche en Electromagnétisme, EMG - Département Electromagnétisme - L2S, Laboratoire des signaux et systèmes (L2S), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-SUPELEC-Campus Gif, Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE), and Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA))

Subjects
Engineering, Spatial-domain dyadic Green function, business.industry, Mechanical Engineering, Acoustics, Edge (geometry), Condensed Matter Physics, Signal, Narrow crack, Volume integral, Coupled integral equations, Multilayered medium, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Planar, [MATH.MATH-MP]Mathematics [math]/Mathematical Physics [math-ph], Eddy-current testing, Fasteners inspection, Rivet, Electronic engineering, General Materials Science, Eddy current testing, business, Aerospace, Boundary element method
Abstract

International audience; Rapid and accurate modeling of Eddy Current Testing (ECT) signal is required in many industrial areas. For example, crack detection via ECT is widely employed in aeronautics and aerospace industry to inspect riveted planar multilayered structures. In these structures, small narrow cracks (e.g. micro-cracks) may initiate at the edge of rivet holes (which can be considered as large volumetric flaws) and propagate through the PMS. This article proposes a new and efficient model, based on a coupled approach between Volume Integral Method (VIM) and Boundary Element Method (BEM), simulating ECT probe signals due to the presence of both narrow cracks located near volumetric flaws within a given PMS. Simulation results are compared with experimental and simulated signals obtained with a numerical code. The performance of the method, in terms of accuracy and computational time, is discussed and the perspectives opened are presented.

Published
2014

10. A fast integral equation model with a dedicated Green’s kernel for eddy-current inspection of fastener holes in driver pickup mode

Author

Konstantinos Pipis, Anastassios Skarlatos, Dominique Lesselier, Theodoros Theodoulidis, Lesselier, Dominique, Département Imagerie et Simulation pour le Contrôle (DISC), Laboratoire d'Intégration des Systèmes et des Technologies (LIST), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire des signaux et systèmes (L2S), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), MEANDER, Department of Mechanical Engineering, University of Western Macedonia [Kozani] (UoWM)-University of Western Macedonia [Kozani] (UoWM), L. J. Bond, D. E. Chimenti, and Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA))

Subjects
Physics::Fluid Dynamics, [SPI]Engineering Sciences [physics], [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Integral Equation Method, Eigenfunction Expansion, [MATH.MATH-MP]Mathematics [math]/Mathematical Physics [math-ph], [SPI] Engineering Sciences [physics], Eddy-Current Testing Modelling, Physics::Geophysics
Abstract

978-1-4613-8027-6; International audience; A fast integral equation model for the eddy-current signal calculation of thin cracks breaking the wall of a boreholein a conducting plate is presented. The model is based on the surface integral equation formalism using a dedicated Green’sfunction, which takes into account the effect of the borehole. The approach followed for the construction of the Green’s kerneland the primary field is the Truncated Region Eigenfunction Expansion (TREE) method.

Published
2014

11. ECT simulation of complex narrow cracks in planar multi-layered structures

Author

Roberto Miorelli, Christophe Reboud, Dominique Lesselier, Nikolaos Poulakis, Theodoros Theodoulidis, Département Imagerie et Simulation pour le Contrôle (DISC), Laboratoire d'Intégration des Systèmes et des Technologies (LIST), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire des signaux et systèmes (L2S), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), MEANDER, Department of Mechanical Engineering, University of Western Macedonia [Kozani] (UoWM)-University of Western Macedonia [Kozani] (UoWM), J. M.A. Rebello, F. Kojima, T. Chady, Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), DRE - Département de Recherche en Electromagnétisme, EMG - Département Electromagnétisme - L2S, Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-SUPELEC-Campus Gif, and Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)

Subjects
dyadic Green function, Eddy Current Testing (ECT), [SPI]Engineering Sciences [physics], [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, semi-analytical modeling, layered medium, Eddy current testing, Boundary Element Method (BEM), conductive planar multilayered structures (MLS), narrow cracks, boundary element method
Abstract

International audience; A fast simulation tool of Eddy Current Testing (ECT) inspections, based on a Boundary Element Method (BEM), is proposed in this paper. Simulated signals consist in impedance variation of a coil due to multiple narrow cracks located in conductive planar multilayered structures (MLS). The cracks can have various shapes or orientations and can lie in any layers of the structure inspected. After a presentation of the method, validations results, consisting in comparison of simulated signals with experimental data and results obtained with finite element calculations, are presented. In all the problems tested, a very good accuracy and a very low computation time have been observed. Further perspective and conclusions of this work are detailed at the end of the paper.

Published
2014

12. Efficient modeling of ECT signals for realistic cracks in layered half-space

Author

N. Poulakis, Roberto Miorelli, Christophe Reboud, Dominique Lesselier, Theodoros Theodoulidis, Département Imagerie et Simulation pour le Contrôle (DISC), Laboratoire d'Intégration des Systèmes et des Technologies (LIST), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, MEANDER, Department of Mechanical Engineering, University of Western Macedonia [Kozani] (UoWM)-University of Western Macedonia [Kozani] (UoWM), University of Western Macedonia [Kozani] (UoWM), Technological Educational Institute of Western Macedonia [Grevena] (TEIWM), DRE - Département de Recherche en Electromagnétisme, EMG - Département Electromagnétisme - L2S, Laboratoire des signaux et systèmes (L2S), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-SUPELEC-Campus Gif, Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), This work was supported by the CIVAMONT project, aiming at developing scientific collaborations around the nondestructive testing simulation platform CIVA developed at CEA, LIST, and Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA))

Subjects
Computer science, Computation, 02 engineering and technology, 01 natural sciences, discrete complex image method, boundary element method, dyadic Green function, [MATH.MATH-MP]Mathematics [math]/Mathematical Physics [math-ph], Eddy-current testing, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, Boundary element method, narrow cracks, 010302 applied physics, Computer simulation, 020206 networking & telecommunications, generalized pencil of function, Half-space, Boundary knot method, Finite element method, Electronic, Optical and Magnetic Materials, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Eddy current testing, layered media, Algorithm
Abstract

International audience; Efficient modeling of Eddy Current Testing (ECT) signals is needed in many areas of industry. Probes design may be improved, and experimental signals interpretation may be better understood by using dedicated numerical simulation tools, provided that they are computationally effective and accurate, while remaining easy enough to be employed at end-user's level. A Boundary Element Method (BEM), dedicated to the numerical simulation of ECT signals due to complex narrow cracks affecting a Planar Multilayered Structure (PMS) and presenting arbitrary orientations is investigated herein. The theoretical formulation relies on the calculation of the dyadic Green operator, associated to the PMS, via appropriate vector wave functions expansions. Then, the use of the Discrete Complex Image Method followed by the application of the Generalized Pencil of Function (GPOF) method is proposed for the efficient computation of this operator. Validation results of the complete model, by comparison with experimental data in laboratory controlled condition and with data provided by a finite-element code, are presented and discussed.

Published
2013

13. Eddy current modeling of narrow cracks in planar-layered metal structures

Author

Christophe Reboud, Dominique Lesselier, Roberto Miorelli, Theodoros Theodoulidis, Département Imagerie et Simulation pour le Contrôle (DISC), Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, DRE - Département de Recherche en Electromagnétisme, EMG - Département Electromagnétisme - L2S, Laboratoire des signaux et systèmes (L2S), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-SUPELEC-Campus Gif, Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE), Department of Mechanical Engineering, University of Western Macedonia [Kozani] (UoWM), and Laboratoire d'Intégration des Systèmes et des Technologies (LIST)

Subjects
narrow cracks, Computer science, Acoustics, 02 engineering and technology, eddy current testing (ECT), 01 natural sciences, law.invention, Reliability (semiconductor), Planar, law, Eddy-current testing, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Eddy current, Electrical and Electronic Engineering, Electrical conductor, Boundary element method, 010302 applied physics, Discrete complex image method (DCIM), 020206 networking & telecommunications, Integral equation, Finite element method, Electronic, Optical and Magnetic Materials, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, dyadic Green functions (DGF)
Abstract

International audience; Eddy current testing (ECT) of narrow cracks is an important issue in several industrial areas. Efficient modeling tools are required in order to better interpret measurements, to design adapted probes, and to assess the reliability of testing procedures. A dedicated boundary element model (BEM) suitable for eddy current inspection of several narrow cracks affecting a planar-stratified conductive medium is proposed. The cracks' openings can be arbitrarily small, and their respective orientations be along parallel or orthogonal directions. The approach alleviates most of the computational difficulties of classical methods in such peculiar cases. Comparisons of the results with experimental and simulated data taken from the literature, completed with in-house experiments, illustrate its good accuracy and low computational burden.

Published
2012

14. BEM modeling for ECT simulation of complex narrow cracks in multilayered structures

Author

Roberto Miorelli, Dominique Lesselier, Theodoros Theodoulidis, Christophe Reboud, Département Imagerie et Simulation pour le Contrôle (DISC), Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, MEANDER, Department of Mechanical Engineering, University of Western Macedonia [Kozani] (UoWM)-University of Western Macedonia [Kozani] (UoWM), DRE - Département de Recherche en Electromagnétisme, EMG - Département Electromagnétisme - L2S, Laboratoire des signaux et systèmes (L2S), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-SUPELEC-Campus Gif, Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE), D. O. Thompson and D. E. Chimenti, and Laboratoire d'Intégration des Systèmes et des Technologies (LIST)

Subjects
010302 applied physics, Engineering, business.industry, multilayers, Experimental data, Structural engineering, 01 natural sciences, PACS 62.20.mt,81.40.Np,81.70.Ex, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Planar, boundary-elements methods, Eddy-current testing, 0103 physical sciences, cracks, business, 010301 acoustics, eddy current testing
Abstract

ISBN-13: 978-0-7354-1129-6 ; ISSN: 0094-243X (print) - 1551-7616 (online); Simulation of Eddy Current Testing (ECT) signals due to real cracks constitutes a matter of interest in many industrial fields. Such complex flaws can be modeled as a succession of narrow crack with canonical shapes (i.e. slot, elliptical, semi-elliptical, etc.) having arbitrary positions and orientations. This paper present a semi-analytical model dedicated to the simulation of ECT inspections of stratified planar structures, affected by narrow crack. Validation of the developments, carried out with experimental data or by comparison with other numerical results, are then discussed.

Published
2012

15. Fast simulation method of multiple narrow cracks in planar stratified media

Author

Roberto Miorelli, Christophe Reboud, Dominique Lesselier, Theodoros Theodoulidis, Département Imagerie et Simulation pour le Contrôle (DISC), Laboratoire d'Intégration des Systèmes et des Technologies (LIST), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, DRE - Département de Recherche en Electromagnétisme, EMG - Département Electromagnétisme - L2S, Laboratoire des signaux et systèmes (L2S), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-SUPELEC-Campus Gif, Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE), Department of Mechanical Engineering, University of Western Macedonia [Kozani] (UoWM), B. Rao and T. Jayakumar and K. Balasubramanian and B. Raj, and Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA))

Subjects
generalized pencil of functions method, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, semi-analytical modeling, Eddy current testing, thin cracks, discrete complex image method, boundary element method
Abstract

International audience; This contribution presents a fast simulation technique of eddy-current testing (ECT) signals due to thin cracks embedded in a planar stratified medium. Starting from the Boundary Element Method (BEM) approach for ideal and narrow cracks, a collaborative work by the authors has led to the development of a more general semi-analytical model treating several parallel and/or orthogonal thin cracks embedded in a planar multilayered structure, without any constraint on the numbers of layers or flaws. Simulation results obtained with this method have been compared with experimental data, results from literature and Finite Element Method (FEM). The theoretical approach and results obtained are presented and discussed, as well as some perspectives for further developments.

Published
2012

16. Modélisation du contrôle par courants de Foucault d'entailles de très faibles ouvertures

Author

Roberto Miorelli, Christophe Reboud, Dominique Lesselier, Theodoros Theodoulidis, Département Imagerie et Simulation pour le Contrôle (DISC), Laboratoire d'Intégration des Systèmes et des Technologies (LIST), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, DRE - Département de Recherche en Electromagnétisme, EMG - Département Electromagnétisme - L2S, Laboratoire des signaux et systèmes (L2S), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-SUPELEC-Campus Gif, Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE), Department of Mechanical Engineering, University of Western Macedonia [Kozani] (UoWM), and Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA))

Subjects
[SPI.ELEC]Engineering Sciences [physics]/Electromagnetism
Abstract

International audience; Le contrôle non destructif (CND) de défauts de très faible ouverture est un enjeu important dans un certain nombre de secteurs industriels comme ceux de l'aéronautique, des transports et de l'énergie nucléaire. Souvent dus à des phénomènes de fissuration de fatigue ou de corrosion sous contrainte, ces défauts peuvent être à l'origine de ruptures brusques des pièces affectées. Dans ce contexte, l'utilisation d'outils de modélisation peut apporter une aide à la mise au point de procédés de détection par courants de Foucault (CF) efficaces. Le CEA développe depuis plusieurs années pour la modélisation du CND par CF des outils semi-analytiques fondés sur l'approche des équations intégrales de volume. Cette approche n'étant pas adaptée à la modélisation de défauts très fins, une nouvelle approche fondée sur la méthode des équations intégrales de frontières a été implémentée dans le cas d'un milieu plan stratifié affecté d'un ou plusieurs défauts parallélépipédiques parallèles. Cette approche est très efficace en temps de calcul car elle ne nécessite qu'une discrétisation surfacique du défaut. Les résultats obtenus dans plusieurs cas de benchmarks se comparent aux résultats expérimentaux de référence avec un très bon accord. Des comparaisons numériques dans les cas d'un défaut infiniment fin d'une part et dans celui de défauts parallèles d'autre part sont également présentées.

Published
2011

17. Semi-analytical simulation of eddy current testing signals due to narrow cracks embedded in a multilayered planar medium

Author

Roberto Miorelli, Christophe Reboud, Dominique Lesselier, Theodoros Theodoulidis, Département Imagerie et Simulation pour le Contrôle (DISC), Laboratoire d'Intégration des Systèmes et des Technologies (LIST), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, DRE - Département de Recherche en Electromagnétisme, EMG - Département Electromagnétisme - L2S, Laboratoire des signaux et systèmes (L2S), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-SUPELEC-Campus Gif, Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE), Department of Mechanical Engineering, University of Western Macedonia [Kozani] (UoWM), Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), and Lesselier, Dominique

Subjects
[SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, [SPI.ELEC] Engineering Sciences [physics]/Electromagnetism, boundary elements method (BEM), Generalized Pencil Of Function method (GPOF), non-destructive testing, multilayered slab, eddy current, narrow cracks
Abstract

ISSN 1559-9450 - http://piers.org/piersproceedings/piers2011Marrakesh.php; International audience; Fast and accurate simulation of eddy current testing (ECT) of thin cracks in conductive pieces using standard numerical or semi-analytical volumetric models is still a matter of concern nowadays, due to the small --compared to the skin depth-- dimension of the cracks in their opening direction. The formalism of the boundary elements method (BEM) has been proposed in the literature to treat the case of an ideal crack. A recent improvement on this method carries out the evaluation of the dyadic Green function analytically in the spatial domain by using the well-known Sommerfeld identity combined with the Generalized Pencil Of Function method (GPOF). This approach has shown to considerably improve the performance in terms of computation time since the fill-time of the moment matrix involved is drastically reduced, a very good degree of precision being still achieved. Starting from these results obtained in the case of a plate, a collaborative work by the authors has been started that aims at developing a quite general semi-analytical model dedicated to the simulation of ECT signals that are due to multiple thin cracks embedded in multilayered planar structures. Two developments are presented in this contribution: the medium containing the crack is first generalized to a non-magnetic multilayered structure. The global performance of the model appears very satisfactory in comparison to volumetric models, as only the flawed region needs to be meshed in two dimensions. Synthetic results obtained in so doing are compared to measurements from well-known benchmark cases as well as to numerical results obtained with volumetric models. The modelling of problems involving multiple cracks in a planar layered medium is also introduced. First results, as well as further improvements of the model currently in progress, are discussed.

Published
2011

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