Effect of different factors on the acoustic absorption of coir fiber

Abstract

The aim of this study was to explore and analyze the effect of different factors on the absorption of coir fiber using the developed analytical techniques employing Johnson-Allard rigid frame model. Estimated results were verified by the measurements conducted in impedance tube on normal incidence sound absorption of coir fiber. It was found that the developed analytical method can provide a well consistent agreement with the experimental results. Factors that may have positive or negative effect are elaborated in this study. It describes how the physical elements of coir fiber absorber panel can change the absorption behavior. Results obtained show that layer thickness and fiber diameter have a significant effect on the absorption, whereas bulk density does not have any considerable effect. In addition, an example is presented in order to show the approaches of enhancing the absorption utilizing the advantage of modification in the physical elements. It exhibits that properly chosen fibers along with suitable amount of bulk density can increase the absorption for the same layer thickness. It indicates that these analyses can be powerfully exploited to improve the absorption of coir fiber and at the same time maintain a reasonable thickness which would be very efficient for limited space structure. Moreover, these results can serve as a guideline for the future implementation of acoustic absorber using naturally collected coir fiber.