Active control of sound radiation and transmission into a cavity consisting of multi-flexible plates

This paper presents an investigation into the active control of sound radiation and transmission into a structural-acoustic coupled system. A rectangular enclosure involving two simply supported flexible plates is considered. One of the two plates is driven by the combination of a point force and incident plane wave. The characteristics of the coupled system with two plates are described by a modal superposition method. The differences between our model and one-plate model are analyzed. Then, the locations of point force actuators for effective control are determined by considering three aspects: the noise reduction level, control force amplitude and structural vibration level. The control mechanisms and performances for the enclosure are determined when one, two and three control forces are applied on one of the plates. The results demon¬strate that acoustic potential energy in the enclosure, kinetic energy of the two plates and the maximum amplitude of optimal control force are greatly reduced when multiple actuators are used. Considering the practical feasibility, the local control is also examined, and the performances of the local and global control are compared by simulations.