Kajian Penggunaan Serat Batang Pinang Raja Dengan Komposisi 50% Serat Sebagai Material Peredam Suara Pada Kap Mesin Mobil

Abstract

This study aims to determine the characteristics of silencers, thermal properties, noise reduction with variations in measurement distance, and the process of making natural fibre acoustic materials into silencers on the car hood. The process of making sound-absorbing material using the casting method is then emphasized using a mould lock. The composition of the sound-absorbing material is 50% rod areca nut fibre with 32 mesh and 50% is a mixture of gypsum and polyurethane. The results obtained for the maximum sound dampening characteristic value (α) of 0.7162 occur at a frequency of 125 Hz and a minimum of 0.4532 at a frequency of 1500 Hz. The thermal properties of the sound-absorbing material were obtained by using DTA. The results of the DTA test showed that at a temperature of 318oC the sound-absorbing material started to burn. The reduction in noise level is obtained by comparing the hood using a silencer and without using a silencer with an SPL measuring instrument on a stationary engine without load and under load. The measurement results show that the percentage of the average decrease on the X- side is 1.01% and X-' is 10.14%, X+ side is 7.54% and X+' is 4.81%, Z- side is 2, 77% and Z-' is 11.46%, Z+ side is 13.25% and Z+' is 3.86%. The conclusions obtained from this study indicate that the silencer made of rod areca nut raja mesh 32 with a polyurethane and gypsum matrix is suitable for use as a sound absorber on a car hood