Thermo-acoustic behaviour of 3D knitted spacer fabrics

Abstract

Nowadays, the utilization of 3-Dimensional (3D) porous textile materials by the civil and mechanical engineers for improved thermo-acoustic environment has widened the research scope. Since spacer textile fabrics have superior thermal and acoustic characteristics compared to conventional woven/knitted structures or nonwovens due to their wonderful 3D sandwich pattern and porous nature. Hence this research paper presents an experimental investigation on the sound absorption behavior and thermal properties of 3D knitted spacer fabrics. The Sound absorption coefficient (SAC) and thermal conductivity (K) were measured using two microphone impedance tube and thermal conductivity analyzer (TCi). Moreover, tortuosity of the spacer fabrics was carefully calculated analytically and compared with experimental results. This study deeply discusses the influence of material parameters and characteristics on acoustic properties of 3D spacer knitted fabrics. The results show that the fabric surface property, porosity, flow resistivity and tortuosity have significant effects on the sound absorbability as well as thermal conductivity. Finally the paper describes regression equations and correlation between Noise reduction coefficient (NRC) and Thermal conductivity (K) for this knitted spacer fabrics. The equation is useful to determine NRC value by knowing the K-value and vice versa for designing the material for various applications.