DESIGN GUIDELINES FOR THE ACOUSTIC PERFORMANCE IMPROVEMENT OF A PERIODIC POROUS MATERIAL

In this paper, some guidelines are provided in order to predict at which frequency the 1 st performance peak (related to periodicity effects: half of the wavelength = periodicity dimension) appears, together with its amplitude, as functions of the unit cell dimensions. Conversely, also the link between the unit cell dimensions and the 1 st performance peak amplitude as functions of the design frequency is shown. Furthermore, some additional guidelines are provided in order to predict at which frequency the 1 st performance peak appears, together with its amplitude, as functions of the foam airflow resistivity.