Active Acoustic Insulation System with Quasi-Zero Stiffness Supported Nonlinear Moving-Coil Diaphragm

Abstract

Active acoustic insulation systems tend to suffer from narrow insulation frequency bandwidth and low-frequency deficiencies. In this paper, we employed a quasi-zero stiffness supported nonlinear moving-coil diaphragm to such a system to achieve the target energy transfer, and broaden the insulation frequency bandwidth. We established the electromechanical acoustic coupling model of the nonlinear active acoustic insulation system, and approximated the frequency response of the acoustic pressure transmissibility using the harmonic balance method. The analytical results for the same were well supported by numerical methods. Further, we analyzed the effect of geometrical parameters and shunting circuit gains to study the mechanical and electrical effects on insulation performance. A semi-physical simulation model was finally set up to validate the theoretical analysis. We discovered that a properly configured active acoustic insulation system could greatly reduce the sound levels and effectively expand the insulation frequency bandwidth.

Keywords: Active acoustic insulation, Nonlinear moving-coil diaphragm, Quasi-zero stiffness, Shunt circuit