Active acoustic insulation system with quasi-zero stiffness supported nonlinear moving-coil diaphragm

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 were well supported by numerical methods. Further, we analyzed the effects of geometrical parameters and shunting circuit gains to explore the mechanical and electrical effects on insulation performance. An experimental design and a semi-physical simulation model were finally set up to validate theoretical analysis. It was revealed that a properly configured active acoustic insulation system could greatly reduce the sound levels and effectively expand the insulation frequency bandwidth.