An active control approach for improvement of sound insulation performance of a double-panel structure

Double-panel structures (DPSs) have wide applications in noise control engineering, but their sound insulation (SI) performances deteriorate rapidly in the low-frequency range. To make up for this deficiency, an active control strategy through controlling the boundary conditions of the sound field is presented to improve the SI performance of DPSs. A controllable plate as a controllable boundary condition is incorporated into the boundaries of the interlayer sound field (ISF), and it can be actively controlled by applying control forces. The control forces are optimized by three control objectives, i.e., minimization of kinetic energy of the radiation panel, minimization of acoustical potential energy of the ISF, and minimization of radiation sound power of the low-order acoustic radiation modes. The control effects, control mechanism, and the influences of the geometrical parameters, number of controllable plates, and location of control force on the SI performance are investigated. The results indicate that in the low-frequency range, all three active control strategies can enhance the SI performance of a DPS. And the modal response calculations indicate that the control mechanism belongs to the acoustical and structural modal suppression and rearrangement. This research provides a solution for improving the low-frequency SI performance of engineering structures.