Sound Absorption Behavior of Knitted Spacer Fabrics

This paper presents an experimental investigation on the sound absorption behavior of knitted spacer fabrics. Both weft-knitted and warp-knitted fabrics were used in the study due to their different structure features. The weft-knitted spacer fabric used was composed of two varied plain knitted outer layers and one textured polyester multifilament spacer layer, and it was considered as a porous sound absorber. The warp-knitted spacer fabric used was made with mesh structure on the outer layers and monofilament yarn in the spacer layer, and it was considered as microperforated panel sound absorber. The noise absorption coefficients (NACs) of these two kinds of fabrics under both single and multilayer forms as well as their combinations were tested using a two-microphone impedance measurement tube. The results show that the fabric surface structure and thickness, spacer yarn type and their connecting ways, fabric combinations and their arrangement methods have significant effects on the sound absorbability. The results also demonstrate that good sound absorbability could be achieved by using knitted spacer fabrics if suitable fabric structures and combinations are used.