The Thickness Effects on Acoustic Properties of Oil Palm Trunk Natural Fiber in Density of 170 Kg/m3

Abstract

The awareness about the harmful effect on fiberglass as sound absorbing material on human health and environment has increased. Thus, the demand for natural fiber to replace fiberglass panel is expanding due to low cost in fabrication and more environmentally friendly. This research has studied the thickness effects on microstructure and acoustic properties of low-density fiberboard (170 kg/m3 ) based natural fiber of Oil Palm Trunk (OPT). The morphologies and acoustic properties of all samples were examined using Scanning Electron Microscope (SEM) and Impedance Tube Method (ITM), respectively. The SAC values for all samples showed a minimum value of 0.8 at frequency range of 2500 Hz – 6400 Hz except for sample with thickness of 10 mm. However, the SAC values of sample with thickness of 10 mm almost reach unity (~0.99) at frequency range of 6000 Hz – 6400 Hz. SAC values are found to increase with increasing in thickness at frequency range of 0 – 3500 Hz except for sample with thickness of 12 mm. As the frequency increased from 5500 to 6400 Hz, the SAC values increased with decreasing in thickness with exception of sample 12 mm. Tortuosity, where it reflects the percolation paths may play a crucial role in determining the SAC at frequency range of 0 – 3500 Hz. The SAC values in frequency range of 0 – 2500 Hz have been fitted in linear equation. The results show that the experimental SAC values for all samples fitted well in linear equation, where the linear correlation, R2 for all samples is above 0.98