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, Cette thèse porte sur le développement d'un traducteur ultrasonore multi-élément capacitif à couplage air (MEACUT) et son utilisation dans le domaine du contrôle non destructif (CND) de matériaux. Un modèle est employé pour simuler numériquement ce traducteur, et pour optimiser sa conception. Un prototype est ensuite fabriqué, puis caractérisé expérimentalement pour quantifier ses performances. Son originalité réside dans le fait qu'il possède une large bande passante en fréquence, tout en offrant la possibilité d'une focalisation variable. Ce prototype est alors employé pour la détection d, Transducteurs ultrasonores capacitifs multiéléments à couplage air pour un contrôle non destructif à focalisation dynamique de matériaux-Modélisation, simulations numériques et expériences

, Il est clairement constaté que la résolution spatiale du procédé d'inspection employé (C-scan) est fortement améliorée grâce aux performances techniques du MEACUT. Enfin, un modèle hybride 3D est développé pour simuler, rapidement et intégralement, ce procédé de CND. Le très bon accord obtenu entre prédictions numériques et mesures expérimentales laisse présager que cet outil de simulation pourra servir à mettre au point d'autres expérimentations de CND

, Mots clés : Couplage air, Transducteur ultrasonique capacitif, Contrôle Non Destructif, Simulation par éléments finis, Méthode analytique, Modèle hybride

, Multi-element air-coupled capacitive ultrasonic transducer with dynamic focusing for non-destructive testing of materials-modelling, numerical simulations and experiments