A study of factors influencing sound absorption properties of porous materials

Abstract

A big accent is put on environmental protection at the present time. Noise belongs in general to negative factors of our environment. For this reason, it is necessary to perform suitable measures in order to eliminate noise. For example, it is possible to apply sound absorbers in order to damp noise. Materials with porous, spongy and fibrous structure belong generally to suitable materials in terms of noise damping. The aim of the paper is to investigate sound absorption properties of different types of porous materials. Frequency dependencies of the sound absorption coefficient over a frequency range of 150-6400 Hz were determined by the transfer function method using the acoustic impedance tube. Different factors, that have influence on sound absorption of the investigated porous materials, were studied in this paper. It can be concluded that sound absorption properties of the tested porous materials are significantly influenced by material structure and thickness, excitation frequency and air gap size behind the investigated samples.