Sound absorption properties of composite structure with activated carbon fiber felts

Abstract

This paper is intended to study the influence of different factors on the sound absorption properties of composite structure with activated carbon fiber felts. Activated carbon fiber felts made from viscose fiber mats were prepared and later combined with perforated panels to form four different composite sound absorption structures. Based on the transfer function method, the impedance tube was used to test the sound absorption coefficients of composite structure in an acoustic range of 80-6300 Hz frequencies. Analysis was made to discuss the influence of such factors on the sound absorption properties as the position of activated carbon fiber felts, thickness, and air space. The results demonstrated that the composite structure displayed different sound absorption properties at different frequencies.Perforated panels played the dominant role in sound absorption by the occurrence of resonance at 80-3500 Hz frequencies, while porous materials contributed the most at 3500-6300 Hz frequencies. At 80-3500 Hz frequencies, the best performance could be observed in the third type of composite structure with changes in the position of activated carbon fiber; the first resonance frequency of the first type of composite structure and perforated panel structure was basically the same, and that of the remaining three types significantly shifted towards the low frequencies with the same scale. In smaller thickness range, with the increase in the thickness of activated carbon fiber felts, sound absorption coefficients of the first and second types of composite structure increased, the first resonance frequency of the first type showing no apparent shift towards the low frequencies compared with what was shown in the second type; but when the thickness arrived at 15.6 mm, sound absorption properties of the composite structure had similar traits to that performed by porous materials in an acoustic range of 80-6300 Hz frequencies. With the increase in the distance of air space, sound absorption properties were improving at 80-650 Hz frequencies but decreasing at 650-3500 Hz frequencies, the first resonance frequency moving towards the low frequencies. At 3500-6300 Hz frequencies, as the position of activated carbon fiber felts and the distance of air space varied, sound absorption coefficients were basically unchanged; while as thickness increased, sound absorption coefficients improved.

Carbon Nanomaterials: A New Sustainable Solution to Reduce the Emerging Environmental Pollution of Turbomachinery Noise and Vibration

“…Chen and Jiang (Chen and Jiang, 2007 ) found that the sound absorption performance of the activated carbon fiber composite is superior to that of other composites. Based on this, Shen and Jiang ( 2016 ), Shen and Jiang ( 2014a , b ) established a sound absorption theory model of activated carbon fiber materials by referring to the circular tube theory model and tested the sound absorption coefficient of the activated carbon fiber sensed in the frequency range of 250–6,300 Hz using a dual-channel impedance tube acoustic analyzer. The result showed that the established sound absorption theory model of activated carbon fiber materials can provide theoretical and technical supports for designing and developing activated-carbon-fiber-based sound absorption materials.…”

Fabrication, sound absorption simulation and performance optimization of multi‐layer gradient fiber‐based composites

“…Recently, Toyoda et al 25 explored the enhancement role of fiber‐based materials in the sound absorption process of MPP/fiber‐based composites. Furthermore, Shen et al 26 combined fiber mat, perforated panel and air layer into four different composites and discussed the effect of the combined structure on the low‐frequency sound absorption properties of the composites. Liu et al 27 calculated the sound absorption coefficients of composites consisting of MPP, porous material and air layer using the transfer function method.…”

Sound absorption properties for multi-layer of composite materials using nonwoven fabrics with kapok

“…The materials that are commonly used for system of sound absorbing using multi-layer structures with porous materials as perforated panels [5][6][7] or microperforated panels [8][9][10][11][12][13][14][15], as they are resistant to humidity, can be designed to provide wide-band sound absorption. Research on sound absorption of multilayer absorbers using fiber porous layers and perforated panel showed that the composed materials had good acoustic properties at low and high frequencies [5,6].…”

“…The materials that are commonly used for system of sound absorbing using multi-layer structures with porous materials as perforated panels [5][6][7] or microperforated panels [8][9][10][11][12][13][14][15], as they are resistant to humidity, can be designed to provide wide-band sound absorption. Research on sound absorption of multilayer absorbers using fiber porous layers and perforated panel showed that the composed materials had good acoustic properties at low and high frequencies [5,6]. A model predicting sound absorption of systems with perforated panel, porous material, and air layers indicated that addition of the perforated panel can improve sound absorption coefficients around the resonant frequency, but ones in other frequency ranges decrease [7].…”