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dc.contributor.advisorShuvalov, Alexander
dc.contributor.advisorPoncelet, Olivier
dc.contributor.authorGOLKIN, Stanislav
dc.contributor.otherCastaings, Michel
dc.date2012-12-21
dc.date.accessioned2020-12-14T21:14:44Z
dc.date.available2020-12-14T21:14:44Z
dc.identifier.urihttp://ori-oai.u-bordeaux1.fr/pdf/2012/GOLKIN_STANISLAV_2012.pdf
dc.identifier.urihttps://oskar-bordeaux.fr/handle/20.500.12278/22328
dc.identifier.nnt2012BOR1A002
dc.description.abstractCette thèse concerne l’étude de la propagation d’ondes acoustiques dans des structures hétérogènes. Le but essentiel de ces travaux est de confronter des résultats d’expériences numériques effectuées dans le domaine physique (espace, temps) à des prédictions analytiques pour la propagation des ondes de surface SH le long d’un demi-espace stratifié périodique produisant des spectres discontinus de dispersion pour les ondes, ainsi que pour la diffusion multiple dans des milieux aléatoires inclusionnaires (fissures, cavités). Le code numérique FDTD développé lors de cette étude a permis, en autres choses, de corroborer quantitativement les fenêtres spectrales théoriques d’existence des ondes de surface dans les demi-espaces périodiques,ainsi que de montrer des zones de validité fréquentielles des approches analytiques de diffusion multiple concernant les propriétés effectives de milieux aléatoires.
dc.description.abstractEnThe study is concerned with acoustic waves in elastic media with a different nature of in homogeneity consisting in either periodically continuous or piece wise variation of material properties, or in random sets of defects embedded into a homogeneous matrix, with a given statistical distribution. The scope of problems is topical in non-destructive testing and other applications of ultrasound.Theoretical methods describing involved acoustic phenomena (complex dispersion features, coherent wave in random media, ensemble average techniques) often rely on certain a priori assumptions which render numerical verification especially important.The thesis presents results of analytical modelling of the propagation of surface acoustic waves along periodic half-space, for which the dispersion spectrum is rather complex (discontinuous spectrum of propagation for the surface waves). A 2nd order FDTD numerical code has been developed in order to perform numerical experiments in the space and time domains, and to corroborate the analytical predictions in the frequency domain. A good agreement of simulated results with analytical modelling demonstrates applicability and consistency of the numerical tool. Finally, the code has been used for extracting numerically the coherent wave regime (mean wave over ensemble averaging of the positions of scatterers) for the acoustic propagation in different types of populations of randomly distributed scatterers. The results indicate ranges of validity of some multiple scattering analytical techniques.
dc.language.isofr
dc.subjectTechnique différences finies spatio-temporelles
dc.subjectMilieux périodiques
dc.subjectOndes acoustiques de surface
dc.subjectSpectre de dispersion
dc.subjectDiffusion multiple
dc.subjectMoyenne configurationnelle
dc.subject.enFinite-difference space-time domain technique
dc.subject.enPeriodic media
dc.subject.enSurface acoustic waves
dc.subject.enDispersion spectrum
dc.subject.enMultiple scattering
dc.subject.enEnsemble averaging
dc.titleSimulation de la propagation d'ondes SH dans des structures périodiques et de la diffusion multiple d'ondes de volume en milieux aléatoires
dc.title.enSimulation of shear surface wave propagation in periodic structures and of bulk wave scattering in random media
dc.typeThèses de doctorat
dc.contributor.jurypresidentPichugin, Aleksey
bordeaux.hal.laboratoriesThèses de l'Université de Bordeaux avant 2014*
bordeaux.hal.laboratoriesInstitut de mécanique et d'ingénierie de Bordeaux
bordeaux.institutionUniversité de Bordeaux
bordeaux.institutionBordeaux INP
bordeaux.type.institutionBordeaux 1
bordeaux.thesis.disciplineMécanique et ingénierie
bordeaux.ecole.doctoraleÉcole doctorale des sciences physiques et de l’ingénieur (Talence, Gironde)
star.origin.linkhttps://www.theses.fr/2012BOR1A002
dc.contributor.rapporteurLe Clézio, Emmanuel
dc.contributor.rapporteurStovas, Alexey
bordeaux.COinSctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.title=Simulation%20de%20la%20propagation%20d'ondes%20SH%20dans%20des%20structures%20p%C3%A9riodiques%20et%20de%20la%20diffusion%20multiple%20d'ondes%20de%20volume%20en%20milieu&rft.atitle=Simulation%20de%20la%20propagation%20d'ondes%20SH%20dans%20des%20structures%20p%C3%A9riodiques%20et%20de%20la%20diffusion%20multiple%20d'ondes%20de%20volume%20en%20milie&rft.au=GOLKIN,%20Stanislav&rft.genre=unknown


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