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Communication Dans Un Congrès Année : 2017

Electromagnetic modeling and imaging of damaged layered fiber-based laminates

Résumé

Layered laminates are widely used in aeronautic and automotive industries due to advantages in weight, stiffness and strength. For the concerned one here, each layer is fabricated by periodically embedding fibers in the homogeneous matrix. Fiber orientations in different layers are set to be the same, but material and radius are allowed to differ. Invisible (to the eye) defects could emerge during the manufacture or in service, and their nondestructive testing is required for evident safety reasons. Electromagnetic (EM) means are an option of interest. Thus accurate EM analyses of the laminates (with and without defects) are needed to estimate EM impacts of defects, and proper imaging approaches should be utilized for robust, high-resolution imaging. Without defects, each layer is periodic and scatting matrices can be built with quasi-periodic theories (C. Li, D. Lesselier, and Y. Zhong, J. Opt. Soc. Am. B, 32, 1539-1549) by properly expanding fields into cylindrical wave expansions (CWEs) or planar wave expansions (PWEs). However, this periodicity is destroyed by defects, thus methods for the sound (undamaged) structure become inapplicable and an advanced modeling approach is to be developed. Missing, displaced, shrunk, expanded fibers, and/or circular homogeneous inclusion inside fibers are considered so far. Their treatment as equivalent sources inside corresponding sound fibers makes the sound laminate as the modeling object, rather than the damaged one. From the scattering linearity, the field solution is a summation of scattering effects due to the exterior source and equivalent ones. While the former apply methods for the sound structure, the latter cases use array scanning method to overcome the singularity of the structure which is caused by the equivalent source inside the fiber. Comparisons with a carefully employed COMSOL solver illustrate the accuracy ensured by the dedicated approach proposed here. As for the location of defects, it is determined by searching for the indexes of fibers including equivalent sources. An enhanced imaging approach involving joint sparsity, which results from the prior knowledge that only few defects are to be found and from the independence of their locations with respect to exterior sources, is explored. Numerical examples show the imaging performances, as well as those of the readily applicable MUSIC approach.
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Dates et versions

hal-01537089 , version 1 (12-06-2017)

Identifiants

  • HAL Id : hal-01537089 , version 1

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Zicheng Liu, Changyou Li, Dominique Lesselier, Yu Zhong. Electromagnetic modeling and imaging of damaged layered fiber-based laminates. 2017 International Applied Computational Electromagnetics Society Symposium in China (ACES-China 2017), Aug 2017, Suzhou, China. ⟨hal-01537089⟩
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