Experimental study on sound absorbing property of spatial absorber of non-woven fabric with micro-perforated plate-like structure

Abstract

Microperforated panel (MPP) absorbers have been widely used in noise reduction and are regarded as a promising alternative to the traditional porous materials. However, the flat panel-like shape restricts their practical use in actual rooms or buildings. To overcome these limitations, three-dimensional MPP spatial sound absorbers have been proposed. MPP are mostly metal materials with high cost. It is relatively easy to make cylinders or cubes, and difficult to make other complex structures. In view of this, a kind of non-woven material which can replace micro-perforated board is proposed in this paper. This kind of non-woven material has the characteristics of low cost, flexibility, convenient moulding and good sound absorption performance. The impedance tube experiments has been employed to study the normal incidence sound absorption coefficient for the non-woven fabric materials. The experimental results show that the sound absorption properties of non-woven fabrics are similar to those of ultra-micro MPP. Three kinds of spatial sound absorbers have been made by non-woven materials. They are the hollow cylindrical, fan-shaped, and honeycomb-like spatial sound absorbers, respectively. The measurement of reverberation chamber results show that the sound absorption capacity of the honeycomb-like spatial sound absorber is better than the hollow cylindrical and fan-shaped spatial sound absorbers. Adding non-woven cylindrical boundary layer can further improve the sound absorption performance of the fan-shaped and honeycomb-like space absorber.