Influence of Fabric Folding Geometry on the Sound Absorption

Abstract

Textile materials used without any other structures show low absorption throughout the operating frequency range, and they are currently used for interior decoration. These fabrics can play an important role in the development of acoustic materials considering folding techniques in the design phase. The folding of a cotton fabric not only affects the esthetic appearance but also directly influences the total absorption surface and the volumetric density. The aim of this research was to establish the influence of geometric design parameters, such as the number of folds and the textile length on the sound absorption properties. Experimental measurements were performed by using an impedance tube considering only incident plane waves. The diffuse-field sound absorption coefficient of several fabric configurations placed in front of a rigid backing forming an air-cavity between them was also measured in the small-sized reverberation chamber. A semi-empirical model based on the spacing between the fabric to the backing wall and the folding geometry was used in order to predict the diffuse-field sound absorption in reverberation room. Results showed a very good agreement between measured and predicted sound absorption coefficients.

Keywords

• sound absorption
• folding geometry
• cotton fabric
• impedance tube
• reverberation chamber
• prediction model