Fabric Sound Depends on Fiber and Stitch Types in Weft Knitted Fabrics

The purpose of this study is to analyze the characteristic fast Fourier transform (FFT) spectra of weft-knitted fabrics, to investigate the relationship between sound parameters and the mechanical properties of the weft knits, and to determine the effects of fiber type and stitch type on the frictional sound and mechanical properties. The specimens included 12 weft-knitted fabrics made from a combination of 3 fiber types (100% wool, 100% cotton and 49%/51% wool/ cotton) and 4 stitch types (plain, rib, half cardigan and half milano stitch). The rustling sounds of each specimen were recorded and analyzed using FFT analysis including sound parameters such as LPT (level pressure of total sound), ΔL (level difference) and Δf (frequency difference). We also used Zwicker's psychoacoustic model to calculate the loudness (Z), sharpness (Z), roughness (Z) and fluctuation strength (Z). In addition, the mechanical properties of the specimens were measured using the Kawabata Evaluation System (KES). The FFT spectra for the weft-knitted fabrics showed different shapes according to the fiber and stitch types. Mechanical properties such as the thickness and weight were correlated with several sound parameters. Fiber type was affected by Δ f and stitch type was affected by ΔL, roughness (Z), fluctuation strength (Z) and weight. Both fiber type and stitch type were affected by tensile properties. It is possible, by changing fiber and stitch types of weft-knitted fabrics, to obtain various kinds of knitted fabrics with different frictional sounds.