Noise attenuation performance of warp knitted spacer fabrics

The development of functional textile structures is important to improve noise attenuation of human life in automotives, residential and occupational environments. In this research, an attempt has been made to find the suitability of three-dimensional (3D) knitted spacer fabrics for sound absorption. Hence, an experimental and analytical investigation on the sound absorption behavior of warp knitted spacer fabrics was conducted. Due to their porous nature, interconnected pores, bulkier and 3D structure, the spacer fabrics have the ability to attenuate more sound energy than conventional materials. This research examined the acoustic properties of spacer fabrics in relation to material parameters such as thickness, density and surface structure and structural characteristics such as massivity, porosity, tortuosity and air flow resistivity. The sound absorption coefficient of the test samples was measured using the impedance tube method by ASTM E-1050 in the frequency range of 50–6400 Hz. The results showed that the acoustic insulation of spacer fabric improves with their thickness and massivity, reduction in their porosity, tortuous path and high air flow resistance. Advance statistical evaluation and two-way analysis of variance is used to analyze the significance of the combined effect of various factors on air flow resistivity and the noise reduction coefficient. These findings are important requirements for the design of spacer fabrics for noise control in the automobile upholstery, buildings, auditoriums, etc.