Analysis of Sound Absorbing Properties of Activated Carbon Fiber Felts Based on Density Change

In order to study the sound absorbing properties of activated carbon fiber felts, three kinds of activated carbon fiber felts with different densities were selected, and the double channel acoustic analyzer with impedance tube was used to test the surface acoustic impedance within 125-2 500 Hz frequency sound waves. Then the four acoustic parameters, that is the sound absorption coefficient, the characteristic impedance, the propagation constant, and the structural constant, were calculated. Finally, the effect of density on the sound absorbing properties of activated carbon fiber felts was analyzed. It was found that with the increase of the frequency, the sound absorption coefficient and the propagation constant of the sample increased, but the characteristic impedance ratio and the structural constant decreased, but the decline was smaller and tended to be stable. With the increase of the density of activated carbon fiber felts, the acoustic parameters of the samples all increased, but the first resonance frequency moved towards low frequency, and the corresponding sound absorption coefficient increased.