Abstract: To suppress the low frequency radiation noise of thin plate, the clamped-clamped rectangular thin plate with partial Macro Fiber Composite piezoelectric is taken as the research object. The related research on the radiation sound active control of the thin plate is carried out. Firstly, the dynamic model of the thin plate structure is established based on the finite element method and verified by the modal test. On this basis, the acoustic radiation model of the thin plate is established based on the elemental radiators method. Secondly, the structure-acoustic controllability index is constructed by combining the structure-dependent radiation modes and the spatial controllability, and the discrete firefly algorithm is used to optimize the actuator positions. Then, the weighted sum of spatial gradients control strategy is adopted for active structural acoustic control, and virtual sensors based on the structural response transmissibility is introduced to realize single error sensing. And the controller is developed by adopting the normalized moment FxLMS algorithm. Finally, the numerical simulation and rapid control prototype experiment are performed. The results demonstrate that the control effect of active control has no significant attenuation after introducing virtual sensors, and the number of error sensors can be reduced. Better results are achieved by optimizing the actuator positions with the structure-acoustic controllability index as the target. The practical effect of active control of thin plate radiated sound under various excitations is remarkable.

Key words: structural sound, active control, weighted sum of spatial gradients, optimization of actuator positions, virtual sensing