In: INTERNOISE 2014 - 43rd International Congress on Noise Control Engineering: Improving the World Through Noise Control. (INTERNOISE 2014 - 43rd International Congress on Noise Control Engineering: Improving the World Through Noise Control, 2014)
Abstract
This paper presents two dimensional sound-proof acoustic metamaterials having tunable multi-band negative effective mass density. The acoustic metamaterial panel was composed of many periodic funnel-shaped cell units into square lattice. Each unit cell operates as multi-band resonators. By tuning unit cell the local reflected acoustic wave was almost out of phase with the incident wave. It leads to the negative effective density and created band gap for absorbing incident sound energy without transmission. Measurement of the transmission loss and negative effective mass density was performed using fourmicrophone methods for characterization of barrier performance