Sound absorption performance of micro-ripped panel

A wideband micro-perforated plate (MPP) resonant absorber usually requires a combination of thin plates, minute holes and high perforation rates, which is difficult to apply on a large scale. To solve the challenge, the MPP was divided into two parts, a supporting one and a sound absorbing one. A micro-ripped panel (MRP) was formed by combining a thick baseplate with large holes and a thin film with micro rips. The acoustic impedance of the MRP was theoretically calculated. The acoustic behaviors inside and outside the aperture, and the acoustic impedance of each part of the MRP were analyzed using simulation tools. Models were established to calculate the impedance end corrections of a micro-slit with large aspect ratio considering the effect of thermal viscosity. It is found that the thick baseplate with large holes could provide good supportive, permeable, and protective effects with small acoustic contributions, and the thin film with micro rips could provide excellent sound absorption performance.