Axisymmetric eddy current inspection of highly conducting thin layers via asymptotic models. (12th October 2015)

• Record Type: Journal Article
• Authors: Haddar, Houssem; Jiang, Zixian
• Is Part Of: Inverse problems. Volume 31:Number 11(2015:Nov.)
• Publication Date: 2015-10-12
• Subjects: axisymmetric eddy current inspection -- asymptotic model -- thickness reconstruction of thin layers; Inverse problems (Differential equations) -- Periodicals; 515.357
• DOI: 10.1088/0266-5611/31/11/115005
• Languages: English
• ISSNs: 0266-5611

Abstract

Abstract: Thin copper deposits covering the steam generator tubes can blind eddy current probes in non-destructive testings of problematic faults and it is therefore important that they are identified. Existing methods based on shape reconstruction using eddy current signals encounter difficulties of high numerical costs due to the layer's small thickness and high conductivity. In this article, we approximate the axisymmetric eddy current problem with some appropriate asymptotic models using effective transmission conditions representing the thin deposits. In these models, the geometrical information related to the deposit is transformed into parameter coefficients on a fictitious interface. A standard iterative inversion algorithm is then applied to the asymptotic models to reconstruct the thickness of the thin copper layers. Numerical tests both validating the asymptotic model and showing the benefits of the inversion procedure are provided.