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Communication Dans Un Congrès Année : 2014

Pulsed eddy current imaging of complex metallic structures

Résumé

An original pulsed eddy current (EC) imaging system dedicated to the advanced non destructive evaluation (NDE) of large complex metallic parts is presented. The system aims at combining the advantages of the pulsed eddy current (PEC) sensors [1] (which enable information relative to defects buried in the investigated part to be extracted through time response analysis) with those of EC imaging devices [2] (which provide spatial time- harmonic EC images of the investigated parts with reduced scanning procedures). The proposed PEC imaging system is based on the combination of a pulsed EC inducer able to excite the part over a large area, and a linear magneto-optical (MO) set-up used to measure the magnetic two-dimensional (2D) impulse response of the investigated part. The sensing is carried out by Faraday effect which occurs in a MO imaging film placed at the surface of the part, and exploited in polarized light. The 2D time response data are acquired by a CCD camera and obtained in a stroboscopic approach. As a result, the device provides data in the form of a temporal succession of high resolution EC images (animation), enabling both the spatial and temporal EC characterizations of the part. Previous works carried out by the authors have shown the relevance of such spatio-temporal investigations to size and discriminate calibrated defects buried in metallic parts [3]. Here, the PEC imaging system device is set and implemented for the investigation of aeronautical lap joints featured by an assembly of three alumium plates bolted together with rivets. Mockups featuring defects of calibrated dimensions (3mm to 8 mm long notches) and located next to the rivet foots at various depthes (0 to 6 mm) are considered. The 2D magnetic impulse responses provided by the PEC imaging system implemented over these mockups allow either time, spatial and spatio-temporal relevant features to be extracted so as to efficiently discriminate defects from rivets. These results open the way to the developpement of new NDE systems providing enhanced characterization possibilities of complex complex metallic structures.
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Dates et versions

hal-01561515 , version 1 (12-07-2017)

Identifiants

  • HAL Id : hal-01561515 , version 1

Citer

Pierre-Yves Joubert, Yohan Le Diraison, Eric Vourc'H. Pulsed eddy current imaging of complex metallic structures. EMSA 2014, Jul 2014, Vienna, Austria. ⟨hal-01561515⟩
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