Factors effecting the acoustic properties of date palm fiber

Abstract

This research focuses on factors that affect the acoustic performance of a porous material, namely date palm fiber (DPF). Natural DPF is chosen as a potential replacement to synthetic fibers which raise a lot of health concerns. DPF is considered as abundant material which can be obtained cheaply and easily, particularly in the Middle East region. Analytical approaches, namely Delany- Bazley, Biot-Allard and Johnson-Allard were used to estimate the acoustical performance of DPF with previously tested natural fiber. All of the analytical values were then validated with the experimental results. Two types of tests, namely acoustic absorption coefficient (AAC) and sound transmission loss (STL) were undertaken to investigate the acoustical performance of the DPF. A series of tests were undertaken to evaluate the parameters that influence the acoustical performance of the samples. These include tests on the sample of DPF panel treated with latex; sample treated with Urea Formaldehyde as well as samples backed with porous material such as woven cotton cloth and polyester. The findings showed that the AAC of DPF improved with the increase in thickness and density. It was also found that there were improvements on the AAC for sample panels backed with porous materials, particularly at low frequency ranging from 90 Hz to 1.6 kHz. In addition, the STL of DPF panels treated with Urea Formaldehyde produced higher acoustic insulation (in the range of 30 dB) due to the increase in panel stiffness. In short, the results showed that acoustical performance of the DPF is slightly less than synthetic fibers, but better than other previously tested natural fibers. This is mainly due to the smaller diameter of DPF as compared to other natural fiber counterparts. The good acoustical performance of DPF suggests that it has a very good potential to replace the currently used synthetic fibers for acoustical treatment application.