Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : March 14, 2019
Acoustic material is used to reduce noise in various places. But, it has low effect in low frequency range. Moreover, large amounts of acoustic materials increase undesirable losses. To solve these problem, we have suggested a method of installing acoustic material by providing air layer in one-dimensional cylindrical tube system. We calculate transmission loss in order to show the difference depending on the presence or absence of air layer. In addition, we calculate frequency at which transmission loss increases by calculating sound pressure amplitude in air layer. We confirm the effect of air layer by experiment using sound tube. It show that the method can be used actually. In case of using same length of acoustic material, multiple air layers provide higher effect than single air layer in experiment. Therefore, the method can be used more effectively by setting acoustic materials so that the number of air layers increases.
