Characterization of Subsurface Defects in Aeronautical Riveted Lap-Joints using Multi-frequency Eddy Current Imaging - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue NDT & E International Année : 2009

Characterization of Subsurface Defects in Aeronautical Riveted Lap-Joints using Multi-frequency Eddy Current Imaging

Résumé

The authors present an original Eddy Current Imager (ECI) designed for the fast and accurate non destructive evaluation of defects buried next to rivets in aeronautical lap joints. The ECI is associated to a signal processing method based on a principal component analysis (PCA) followed by a maximum likelihood (ML) approach. The PCA was implemented using EC images obtained with selected excitation frequencies. These images are considered as resulting from a linear mixing of different sources including the presence of rivets and defects, and the PCA is used to separate these sources thanks to an eigen decomposition of the EC data covariance matrix. As a result, the defect signatures are enhanced and used to implement an automatic defect characterization. This characterization is carried out by the means of an ML approach which allows the length and depth of the defects to be estimated. The method was implemented for the evaluation of a laboratory made riveted lap joint mock-up featuring buried defects. It was experimentally optimized and successfully implemented for the characterization of calibrated defects ranging from 2mm to 10mm in length and 2mm to 8mm in depth.

Dates et versions

hal-00844766 , version 1 (15-07-2013)

Identifiants

Citer

Yohan Le Diraison, Pierre-Yves Joubert, Dominique Placko. Characterization of Subsurface Defects in Aeronautical Riveted Lap-Joints using Multi-frequency Eddy Current Imaging. NDT & E International, 2009, 42 (2), pp.133-140. ⟨10.1016/j.ndteint.2008.10.005⟩. ⟨hal-00844766⟩
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