Employing the micro-perforated panel in the vehicle cabin: Is this possible?

The micro-perforated panel (MPP) has been developed as a sound absorber which replaces the classical synthetic fibrous material. Known as the ‘hygenic’ acoustic material, its optical surface also makes it attractive enhancing the art of a room interior. This paper discusses the possibility to apply the MPP which substitutes the solid panel at the inner side on the double-leaf partition of vehicle structures to control sound absorption in the vehicle cabin. Having known as an important part of modern lightweight structures such as aircraft fuselages, train walls, car doors, windows and lightweight partition walls in buildings, the double-leaf partition has poor noise insulation at low frequencies due to the coupling between the partition masses and the air between them. The presence of the micro holes adds additional damping which breaches this coupling and increases the sound transmission loss. This can be controlled by tuning the properties of the MPP, i.e. the hole diameter, the perforation ratio and the cavity gap. The solid-MPP (SMPP) system therefore provides double functions simulatenously, i.e. as sound absorber and noise barrier. Derivation of the mathematical model for the transmission loss of the SMPP subjected to oblique and diffuse field incidence of acoustic loading is presented