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Etude et réalisation de transducteurs composites pour l'imagerie acoustique et le contrôle non-destructif

Abstract : Future developments in acoustic medical imaging and in non-destructive evaluation are conditionned by three-dimensional-imaging requirements, for instance high-density integrated probes and novel imaging practices. Ultrasound probes devoted to imaging applications have become arrays of hundreds or even thousands of elementary transducers, for which one-dimensional models are not well-suited and numerical methods can not be used without refinements. In this work, we study new strategies for modelling and designing imaging ultrasound probes, based on the statement that imaging devices are massively periodic.
With the underlying idea that modern ultrasound probes are manufactured on the basis of piezoelectric
composite transducers, we propose two numerical methods. The first one is based on a finite-element analysis / boundary-element method (FEA/BEM) that takes into account the periodicity of the studied devices
and the propagation media in which the structures radiate. The second method is based on a plane-wave
expansion and it comes from the study of band-gap structures also-called phononic crystals. It provides
one a different approach for the study of piezocomposites. This second approach is liable to lead one to design novel composite patterns that differ from the classical square-section rods of ceramic, and that require alternative fabrication techniques of piezocomposites. Powderblasting and ultrasound-micromachining
techniques have been investigated with the EPFL and the LCEP respectively.
Thanks to its flexibility, the FEA/BEM allows one to simulate a large variety of transducer arrays. It
provides an analysis of the phenomena that occur in such arrays and allows one to estimate cross-talk
effects between the elementary transducers. This approach is applied to a 1-D commercial probe, which is
nowadays the everyday life of designers, and to micromachined ultrasonic transducers that have appeared as a novel concept for imaging applications.
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-00011338
Contributor : Mikaël Wilm <>
Submitted on : Tuesday, January 10, 2006 - 1:04:53 PM
Last modification on : Thursday, November 12, 2020 - 9:42:08 AM
Long-term archiving on: : Saturday, April 3, 2010 - 9:05:10 PM

Identifiers

  • HAL Id : tel-00011338, version 1

Citation

Mikaël Wilm. Etude et réalisation de transducteurs composites pour l'imagerie acoustique et le contrôle non-destructif. Acoustique [physics.class-ph]. Université de Franche-Comté, 2004. Français. ⟨tel-00011338⟩

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