Numerical characterization of the radiation properties of a spatially bound acoustoelectric probes

Thierry Laroche (1) , Stephen Moreira (1) , William Daniau (1) , Julien Garcia (1) , Sylvain Ballandras (1)

1 FEMTO-ST - Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174)

The computation of ultrasonic probes behavior is still a difficult problem to address as it requires the capability to simulate arrays of elementary transducers assembled periodically and radiating in various (open) media. The dimensionality change when considering elementary transducer vibration and the probe radiation imposes to combine computation tools potentially base on different paradigms but capable to be interfaced in that purpose. The use of periodic finite element/boundary element-based (so-called FEA/BEM) softwares in that purpose has not been pushed to its ultimate capabilities and still must receive in interest as it notably saves time computation without sacrifying calculation precision. More it is not limited in probe size as soon as realistic edge conditions can be introduced in the calculation. In this work, we study the acoustic transducers behavior and radiation performances using our periodic FEA/BEM code and a dedicated numerical postprocessing based on the Rayleigh-Sommerfeld formulation for the simulation of near and far field radiation effects. From harmonic FEA/BEM numerical results, we derive the mutual quantities relating the transducer elements one another. We then use the above mentioned postprocessing tool to calculate the radiated properties of the considered probes for any electrical excitation in harmonic regime. From this post-computation, we are able to extract important physical characteristics like the front-side velocity, directivity, crosstalk and the transfer function of the probe accounting for its actual electrical excitation. We first explain how to mathematically work out the radiated pression field and the above mentioned characteristics. We then examine 2 and 3-dimensional representative test cases. We particularly show the influence of the principal transducer parameters (i.e. the transducers array period, the number of transducers in the probe, the excitation mod, etc) on the radiated pressure field.

Domaines: Acoustique [physics.class-ph]; Acoustique [physics.class-ph]

Thierry Laroche, Stephen Moreira, William Daniau, Julien Garcia, Sylvain Ballandras. Numerical characterization of the radiation properties of a spatially bound acoustoelectric probes. 10ème Congrès Français d'Acoustique, Apr 2010, Lyon, France. ⟨hal-00551163⟩