Vibroacoustic characteristic of membrane-type acoustic metamaterials

Abstract

Acoustic barriers with effective sound insulation performance can find many useful applications in the area of aerospace, automotive vehicles and environmental noise control. However, traditional acoustic barriers are always not effective at low frequencies due to the mass law. Membrane-type acoustic metamaterials have been shown to exhibit unique sound insulating performance at low frequencies (100-1000Hz). The structure of membrane-type acoustic metamaterials can be simplified as a stretched, rim fixed membrane carrying a distributed mass. There are publications on beams, rods and plate with uniformly distributed mass, but the vibration equation of membrane is different from the plate, and the presence of air around the membrane needs to be properly included. In this paper, we present an analytical model of this type acoustic metamaterials. The transmission loss and vibration characteristic are then described using the coupled structural-acoustic model. The validity of the model is confirmed by comparing our analytical results with the FEA calculations and experimental measurements in existing publications.