The effect of geometrical variability on the sound absorption performance of meta-poro-elastic systems with small mass inclusions

Poro-elastic materials are widely used as sound absorbing materials. However, they are considered to be ine cient solutions at low frequencies, as a quarter wavelength thickness is needed to absorb the sound. To overcome these limitations, meta-porous and meta- poroelastic materials with periodic inclusions have recently emerged as a potential alternative solution. Since these materials often exploit periodicity, their acoustic performance can be prone to material and geometrical variations due to manufacturing inaccuracies. In this paper, the effect of geometrical variability on the sound absorption performance of a meta-poro-elastic material with periodic small mass inclusions is investigated. This type of meta-poro-elastic material aims to improve the low-frequency sound absorption by exploiting mass-spring and modified mode effects. Using a Monte Carlo Simulation approach with different predefined probability density functions for the mass inclusion positions and sizes, the resulting variability on the sound absorption is assessed. It is found that the absorption performance can be robust against a certain amount of positional variability, although the nominal design frequency can be shifted.