NDTnet 1998 Aug, Vol.3 No.8

Abstract

Fig. modulus of the normal component of the magnetic field Fig.

An eddy current imaging system has the capability to give an image of anomalies such as cracks and notches in a conductive media. In this study, measurements of the magnetic field due to induced current interactions with notches have been used to reconstruct notches shapes through an inversion algorithm. First, we remind the numerical model w- used, firstly, to validate the direct problem. hich relates a contrast function (representative of flaws) and the measured data. This model is based on a system of two equations coupled by the scattered electric field. Then, we compare the measurements performed with an experimental probe with predictive data which come from the numerical model. This comparison is

Second, the solution of the associated inverse problem is regularized through a Bayesian estimation framework. We derive an appropriate criteria which must be optimized in order to reconstruct simulated flaws.

In a third part, the results of some flaw reconstructions from measured data obtained with an experimental probe and mock-up with artificial unduced flaws are presented. For example, the near cartographies show a simulated flaw contrast function, the simulated data, and the results of the inversion procedure (Least Square and the proposed algorithm). The results confirm the validity of the direct and inverse problems and the capability of the eddy current imaging system.

[1] N. Madaoui, D. Premel, and D. Placko, Conception et realisation d'un capteur a courants induits tournants pour la reconstruction tomographique d'image par courant de foucault,NUMELEC, 1997.

[2] D. Premel, and A. Mohammad-Djafari, Eddy current tomography in cylindrical geometry, IEEE Trans. Magn. 31 (1995), no. 3.

Abstract Source:
Book of Abstracts, 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN: 87-986898-0-00

Full-Text Source:
Proceedings of the 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN:

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