Vibration And Research Of Sound Radiation And Control Of The Rectangle Plate

With the development of social economy, noise has been obtained widespread provenance as one of the significant environmental issues. In the past decades, the active noise control has been developed rapidly as a newly arisen discipline, which are expected to overcome the disadvantages of traditional passive noise control techniques in low-frequency stage. Based on the radiation modes, method of active structural acoustic control can avoid the complicated coupling of vibration modal and simplify the calculation and control burden. However, all the existing research production of radiation modes originate from rectangular plates with all four sides simply supported, while noise control about plates with one pair of opposite sides fixed and other two opposite sides free has not been reported yet.The current study is summarized as follows:(1)Based on the modal superposition method, the displacement and velocity formula of plate with two opposite edges fixed and other two free under excitation are deduced by theoretical analysis. Meanwhile, the finite element simulating and MATLAB programming and calculation are also used to confirm the results. Further, approximate solution for sound pressure distribution around the plate is obtained by velocity distribution. All conclusions above can provide a theoretical basis for a further study on sound radiation of plate with two opposite edges fixed and other two free.(2) By the theory of radiation mode, the changing trend about radiation modal,radiation efficiency of each step versus frequency is established. In addition, the correspondence relationship between radiation mode and structure vibration mode are analyzed systemically.(3) Aiming at radiation modal characteristics, two control methods of canceling acoustic radiation coefficient of the first N steps and minimizing acoustic power are presented and then compared for controlling effect. The influence of control effect with different position of exciting force and controlling force is also analyzed preliminarily.The research results show that in low-frequency sound control method based on the radiation mode can reduce the acoustic power of plates with two opposite edges fixed and other two free sharply. And reasonable controlling forces locations will greatly improve the control effect.