Sound absorption of Multilayer Micro perforated Panel with Helmholtz Resonator Mount

摘要

Micro Perforated panel (MPP) for noise control application is the promising alternative to the conventional porous material. However, the absorption frequency range of this MPP alone is not sufficient to contest with the porous material. In order to enhance the sound absorption of single leaf MPP, Helmholtz Resonator (HR) is introduced. In addition to that polyurethane foam is kept as another layer to ensure the one-stop solution for low, mid, and high frequency problem. The acoustic impedance of this configuration evaluated by transfer function method. The theoretical results compared with experimental one and the obtained result shown that it has two resonant frequencies and it is separated by one anti-resonant frequency as well. Later on, there is a shift in the frequency peak obtained due to effect of various neck lengths and diameter of Helmholtz resonator. Further the introduction of multiple parallel resonators results better sound absorption than the single Helmholtz resonator