Skip to Main content Skip to Navigation
Theses

Contribution à la modélisation de systèmes de Contrôles Non Destructifs par Courants de Foucault. Application à la caractérisation physique et dimensionnelle de matériaux de l'aéronautique.

Abstract : The structures of planes are constituted of large metal sheets made of aluminium or composite materials. When these sheets are being formed, several flaws may appear. Through this work, we contribute to the development of models and to the conception of sensors which can detect these flaws. We study the case of aluminium sheets drawn out on ferritic cast iron matrix. This process reduces the thickness of the sheet. Moreover, it generates a gap between the matrix and the aluminium sheet. In order to measure the thickness and the gap simultaneously, we use several ultra-thin coils between the cast iron and the aluminium sheet. The coil impedances are used with an analytical inverse algorithm to obtain information about the thickness or the gap. This system gives satisfying results with regards to the measurement of the gap. The measurement of the thickness is nevertheless more difficult to apprehend with this technique. We therefore use a sensor with a ferrit core above the aluminium sheet. Its impedance is analysed with a model based upon the coupled circuits method. Moreover, this model enables us to take into account both skin and proximity effects in the coil. To complete this work, a 3D Finite Element model with heterogeneous and anisotropic materials is presented. A preliminary homogenization stage of electromagnetic properties precedes an anisotropic shell elements formulation. The sensor resistance variation with regards to the composite sheet is used as information.
Document type :
Theses
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-00260526
Contributor : Vincent Doirat <>
Submitted on : Tuesday, March 4, 2008 - 1:53:59 PM
Last modification on : Tuesday, May 21, 2019 - 6:00:02 PM
Long-term archiving on: : Thursday, May 20, 2010 - 8:50:37 PM

Identifiers

  • HAL Id : tel-00260526, version 1

Collections

Citation

Vincent Doirat. Contribution à la modélisation de systèmes de Contrôles Non Destructifs par Courants de Foucault. Application à la caractérisation physique et dimensionnelle de matériaux de l'aéronautique.. Autre. Université de Nantes, 2007. Français. ⟨tel-00260526⟩

Share

Metrics

Record views

362

Files downloads

361