Sub-wavelength damage detectability assessement in periodic assemblies using a Bloch modelling framework
Résumé
In this work, we develop a numerical framework for analyzing Bloch waves andtheir interactions with localized damages. A reduced Bloch expansion technique is first usedto sub-structure the waveguide’s healthy part, while a detailed finite element description of thedamaged regions can be applied. A remarkable strength of this modelling technique lies in thepossibility to compute the dynamic response of the overall structure (finite or infinite) subjectedto harmonic or transient loads. The damage model and its location on the waveguide can bothbe updated with almost negligible additional computational effort. The performances comparedwith standard finite element analysis of a similar problem are outstanding (i.e. faster by atleast 3 orders of magnitude). Two types of indicators can therefore be computed over a largenumber of possible waveguide-damage configurations: (i) the local transmission, reflectionand conversions of Bloch waves at the interfaces of the damaged region, and (ii) the globalharmonic or transient response of a loaded waveguide. This approach is used to extend thedetectability of small-scaled damages in large-scaled periodic waveguides by exploiting thefrequency-conversions of the Bloch scattering coefficients. These so-called ’diffusion features’are eventually used to improve sub-wavelength damage quantification and localization.
Origine | Fichiers produits par l'(les) auteur(s) |
---|