Sound absorption coefficient analysis and verification of weft-knitted spacer fabrics for noise reduction application

Weft-knitted spacer fabrics with robust sound absorption ability had great application prospects in noise control engineering, but the relationship between structural parameters and sound absorption still required to be investigated further. In this work, a series of wet knit spacer fabrics with different structural parameters were fabricated, and the measured and predicted sound absorption coefficients were also compared. The results showed that the airflow resistivity was mainly determined by their density, thickness, porosity, and yarn arrangement. The sound absorption coefficient of samples can be enhanced with the increasing thickness and airflow resistivity, and the absorption tendency of double layer spacer fabrics assembled by samples with more yarns is coincident to those, and the coefficients were higher than 0.5 above 1000 Hz and higher than 0.8 above 2000 Hz. Sample numbers 6/4, 6/7, 12/10 exhibited the best sound-absorption ability among these samples in the high frequency bandwidth. In sum, the prepared weft-knitted spacer structure (consisting of top and bottom plain-knitted layers) with covered elastomeric yarns, has shown great potential in the application of noise reduction and control engineering.