Acoustic response of a periodic distribution of macroscopic inclusions within a rigid frame porous plate
Résumé
The acoustic response (in particular, the transmission) of a periodic distribution of macroscopic inclusions within a rigid frame porous plate (similar to a sonic crystal) is studied by the multipole method. Numerical results show that the addition of grating stacks leads to bandgaps within the audible frequency range for a small number of stacks, this being associated with a large decrease of the transmission coefficient of the initial plate. The first bandgap is of practical interest for noise shielding, i.e. very low transmission. The second bandgap enables total acoustic absorption within a narrow frequency range due to the fact that a modified mode of the plate lies within this bandgap.