Establishment of acoustic characteristic model of activated carbon fiber felts

Abstract

In order to analyze two basic characteristic acoustic parameters of activated carbon fiber felts: propagation constant and characteristic impedance, the theoretical model of characteristic impedance concerning the two parameters was established by means of motion and continuity equations based on the propagation theory of acoustic waves in activated carbon fiber materials. On the basis of acoustic theories proposed by Zwikker and Kosten, taking into account of the vibrating influence occurring among fibers and modifying the effective air density and the effective bulk modulus, theoretical model of characteristic acoustic parameters of activated carbon fiber materials was established. Surface acoustic impedance was tested with an impedance tube when activated carbon fiber materials were subjected to an acoustic range of 250–2500 Hz frequencies, then propagation constant and characteristic impedance of activated carbon fiber materials were defined by the method of double thickness. Statistics of two acoustic characteristic parameters in theory and trial were compared and contrasted, which showed that the theoretical model had its feasibility and could provide reference for developing and designing the activated carbon fiber materials with sound absorbing properties.

Keywords:

• Activated carbon fiber
• propagation constant
• acoustic characteristic
• the effective density
• the effective bulk modulus

Additional information

Funding

This work was supported by the Grant from National Natural Science Foundation of China (NO.51702167), Scientific and Technological Project, Nantong, Jiangsu, China (NO.JC2018035) and The Advanced Textile Engineering Technology Center Scientific and Technological Project, Jiangsu, China (NO.XJFZ/2018/10).