Sound Absorption Properties and Accuracy of Prediction Models on Natural Fiber Based Nonwoven Materials

In this work, the sound absorption performance of cotton fiber- and wool fiber-based nonwoven fabrics as well as one pure polyester nonwoven fabric were investigated. The Brüel & Kjær two-microphone impedance tube is used to conduct the measurement in the frequency of 50–6400 Hz. Empirical and semi-phenomenological models are used to predict the acoustical impedance and sound absorption coefficient of natural fiber-based nonwoven fabrics. The nonwoven fabric containing 60 wt.% cotton fiber and 40 wt.% polyester fiber shows a comparable sound absorption ability compared with the polyester nonwoven. At the same time, this property for wool-based nonwoven is relatively poor. Moreover, the prediction is still not acceptable, although the Voronina model exhibits better prediction for the natural fiber-based nonwoven materials compared with the other two prediction models. The modification on the Miki model was conducted to fit the cotton and wool fiber-based nonwovens. The modified Miki model demonstrates an accurate prediction on surface impedance and sound absorption coefficient for the natural fiber-based nonwovens.