Experimental evaluation of double-wall soundproof structure using acoustic metamaterial with resonator and membrane

Abstract

In recent years, hybrid vehicles and electric vehicles have become popular. In such vehicles, there is a problem that low and medium frequency noise such as road noise, which has been masked by noise from the engine, is offensive to the ears. The performance improvement of the sound insulation material in the low and middle frequency range can be achieved by increasing the mass and volume of the sound insulation material. However, it must be avoided from the viewpoint of vehicle weight reduction. Acoustic metamaterials are attracting attention in order to suppress low and medium frequency noise without increasing the thickness or mass of the sound insulation material. An acoustic metamaterial is an artificial structure that has a periodic structure smaller than the sound wave length, and has a resonant system in the periodic structure. By applying the acoustic metamaterial to the double-walled structure of the floor of the automobile, improvement of the sound insulation performance in the low and middle frequency range can be expected. In this research, we investigate an experimental evaluation of double wall soundproof structure using acoustic metamaterials with resonator and membrane.