Abstract:

Aiming at kapok-based nonwoven fabrics, a new sound-absorbing model, based on the Allard model is developed based on equivalent fluid method by considering the heat conduction performance of the materials and the limpness of the fiber frame. The sound absorption coefficients and specific surface impedance are calculated by the Allard model and the new model, respectively. The comparisons between the calculated and measured values for four types of kapok-based  nonwoven fabrics are made. It is shown that the new model provides the predictions better than Allard model. This further indicates that the new model is suitable for the charactering of sound absorption for kapok-based nonwoven fabrics, and will lay the theoretical foundation for the design of industrial products for kapok materials.

Key words: kapok fiber, nonwoven fabric, sound absorption model, specific surface impedance, bulk modulus