Calculation of Acoustic Transmission Intensity of 1-D Composite Models for Sound Absorber Wall Application: Case Study on Wood – Epoxy Composite

One application of composite materials is for use as building walls. One characteristic of building walls is they can absorb acoustic waves. Buildings near crowded streets perhaps need the walls which absorb sound better than other areas. This paper presents the calculation of acoustic transmission of 1-D composite model containing two component materials. In general, the wave intensity decreases when it comes to boundary surface of different media, and attenuated during propagation in a medium. The acoustic impedance and attenuation coefficient data used are referred to wood and epoxy. To study the influence of physical properties on the acoustic transmission of the 1-D composites, the output acoustic intensities are calculated for several conditions: different total thicknesses for a pair of wood – epoxy, different fractions of wood (17-58)% for a pair of wood - epoxy, and two different thicknesses: 0.8 cm and 0.4 cm of components for the arrangement of one pair and two pairs of wood – epoxy (50:50), respectively, for the same total thickness. The acoustic transmissions are calculated for incident acoustic intensity of heavy traffic, i.e. 80 dB (10 -4 watt/m 2 ). The results show that the output acoustic intensity of the composite model is lower than that of wood and epoxy. The output acoustic intensity decreases as wood fraction increases. It is also noted that the size of component affected the output acoustic intensity, where the smaller the size, the lower the intensity.