Recent Advances in Modeling Discontinuities in Anisotropic and Heterogeneous Materials in Eddy Current Nde

Aldrin, John C.; Sabbagh, Harold A.; Murphy, R. Kim; Sabbagh, Elias H.; Thompson, Donald O.; Chimenti, Dale E.

doi:10.1063/1.3592116

Cited by 2 publications

(2 citation statements)

References 5 publications

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“…In eddy current testing, these influences can arise from lift-off variation, surface conditions, material-related anisotropy or grain structure [5] . The scatter caused by other influencing factors can be described by a distribution function.…”

Section: Conventional Probability Of Detection Approachmentioning

confidence: 99%

Probability of detection for surface-breaking holes with low-frequency eddy current testing – a non-linear multi-parametric approach

Kanzler¹,

Müller²,

Pitkänen³

2014

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The evaluation of non-destructive testing (NDT) methods in terms of reliability is an increasing demand in various industries and applications. The probability of detection (POD) is the most frequently used method for this task. In the testing of holes with low-frequency eddy current testing, the frequently-used one-parametric POD approach cannot be used because the requirements, mainly the linearity, cannot be met. Therefore, the use of a multi-parametric non-linear regression approach to calculate the POD is proposed. Instead of numerical simulations, commonly used in multiparametric approaches, an analytical model is used. The goal of this work is to evaluate the reliability of the eddy current system for the testing of electron-beam welded copper canisters by calculating a POD with the help of different artificial hole-like defects. In this example, the multi-parametric non-linear regression approach is shown to be successful, enabling the combination of depth and diameter in the POD calculation.

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Section: Conventional Probability Of Detection Approachmentioning

confidence: 99%

Probability of detection for surface-breaking holes with low-frequency eddy current testing – a non-linear multi-parametric approach

Kanzler¹,

Müller²,

Pitkänen³

2014

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“…What poses a real challenge is the determination of complex eigenvalues when the region under consideration consists of several sub-regions (containing conductive material or air). Such a situation occurs when modeling disks [ 8 , 9 , 10 , 11 ], tubes [ 12 , 13 , 14 , 15 , 16 ], rods [ 17 , 18 ], materials with a defect [ 19 , 20 , 21 , 22 , 23 , 24 ], and wherever there are edges [ 25 , 26 , 27 , 28 , 29 ] or discontinuities [ 30 , 31 , 32 ] ( Figure 1 ). Determination of the eigenvalues then boils down to finding complex roots of the appropriate complex function.…”

Section: Introductionmentioning

confidence: 99%

Computation of Eigenvalues and Eigenfunctions in the Solution of Eddy Current Problems

Theodoulidis

Skarlatos

Tytko

2023

Sensors

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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.

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Recent Advances in Modeling Discontinuities in Anisotropic and Heterogeneous Materials in Eddy Current Nde

Cited by 2 publications

References 5 publications

Probability of detection for surface-breaking holes with low-frequency eddy current testing – a non-linear multi-parametric approach

Probability of detection for surface-breaking holes with low-frequency eddy current testing – a non-linear multi-parametric approach

Computation of Eigenvalues and Eigenfunctions in the Solution of Eddy Current Problems

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