Development of Kenaf Nonwoven as Automotive Noise Absorption

Abstract

Getting rid of unwanted noise in car compartment is necessary and really significant measure for automotive makers. This research was directed to produce nonwoven material from Kenaf fiber using the needle-punching machine and the ability of the produced material to absorb sound will be tested. The performance in sound absorption of the sample was analyzed by the sound absorption coefficient (SAC) and noise reduction coefficient (NRC) using the impedance tube test referring to ASTM E1050-98. The sound absorption frequencies were evaluated utilizing the two-microphone transfer function technique in the impedance tube that has a 100 mm diameter for low frequency and 28 mm for high frequency, 0 Hz to 4000 Hz respectively. The physical examination also was executed according to ASTM D1772 to determine the density and the thickness of each sample. The parameter verified in this research is the number of layers to form the samples and it also were compared with the commercial products. As the outcome of this research, the sound absorption coefficient (SAC) showed that the sound reduction coefficient value was increased as the number of layers of the sample increase. In summation, the result also proved that the denser the samples, the higher the absorption coefficient value. On the other hand, for the noise reduction coefficient (NRC), overall result showed slight differences between each sample. The result is due to the rating is an average, two materials with the same rating might not perform the same. Referring to the previous research, the sample with higher areal density is dependable for higher sound reduction and there is a negative relationship between area density and bulk density of needle-punched nonwoven and sound reduction. With the rise in the number of density of nonwoven fabric, the sound reduction through the fabric increases at first but after the maximum it remains almost unaffected.