Tunable acoustic insulation characteristics of membrane-type acoustic metamaterials array with compact magnets

Abstract

This paper presents membrane-type acoustic metamaterials array with compact magnets (MAMMs array) for acoustic insulation. The proposed MAMMs array consist of four cells. Every cell is realized by placing a membrane with a centered magnet in a magnetic field. The magnetic fields of each cell do not affect each other. To clarify the tunable sound insulation characteristics of the MAMMs array, a mode superposition model and the corresponding finite element analysis model were established to predict the transmission loss (TL) of the MAMMs array. Experiments were performed in an impedance tube, and the experimental results agree well with the predicted ones. This research demonstrates that each cell of the MAMMs array is individually adjustable and the enhanced tension of the membrane due to the increased magnetic force leads to the upward shifting of the TL peak frequency and TL peak enlargement in each cell. By optimizing different cells of the MAMMs array, the TL curve of the MAMMs array can produce multiple TL peaks, and the noise isolation of multiple frequency bands can be realized.