Active control of sound transmission through double-panel structure into an enclosure based on controllable boundary condition of sound field

Double-panel structure has a wide range of important applications in transportation vehicles, aerospace, and aeronautical structures and so on. To improve the low frequency sound insulation performance of the double-panel structure, an active control strategy based on controllable boundary condition of sound field is proposed to improve the low frequency sound insulation performance of double-panel structure. Taking advantage of the interlayer space of double-panel structure, the simply supported rectangular plates are embedded into the boundaries of the interlayer sound field as new controllable boundaries, which is named controlled boundary plates (CBPs). The control force is applied at the CBP. Three control objectives, i.e., minimization of total time averaged acoustical potential energy of enclosure sound field (TAPE-E), minimization of total time averaged acoustical potential energy of interlayer sound field (TAPE-I), and minimization of averaged kinetic energy of the low panel (AKE-L), are adopted to optimize the control forces. The results indicate that the arrangement of CBP can significantly alter the vibro-acoustic coupling performance of the overall system. The active control strategy with the three different control objective functions can achieve ideal improvement of sound insulation performance of double-panel. In comparison with point acoustic source, the CBP can be regarded as a combination of multiple monopoles and dipoles, the better control performance can be obtained in high frequency range. In addition, the effects of the dimension, number and location of control force are investigated. Through calculation and analysis, there are two main control mechanisms, i.e., modal suppression and modal rearrangement. This study provides guidelines for the active noise control and the improvement of the low frequency sound insulation performance of the engineering structures.