Study On Piezoelectric Sensor/Actuator Scheme For Active Control Of Sound Radiation From Plate

The system of active structural acoustic control (ASAC) is the application of active vibration control (AVC) in the field of active noise control (ANC), the minimization of the structural sound radiation was achieved by adding the second force to the structure. The intelligent acoustic structure was studied broadly which generally build up with piezoelectric sensors/actuators, structural strain information was measured and corresponding action was given which realize the control of the acoustic radiation from structure. Great efforts always be made by so many scholars to achieve the goal that using a small quantity of sensors/actuators to reduce the sound radiation level to a satisfying one at the low frequency, there are two possible mechanisms by which attenuation of acoustic power can be achieved. The first involves an increase in the input impedance of the primary offending structural modes, resulting in a decrease in their amplitude (model control) . The second is an alteration in the relative amplitudes and phases of the structural modes (model rearrangement). This two mechanisms, modal control and modal rearrangement, can coexist, and do so in varying degrees for the same structure when vibration control sources are attached at different locations. Model control method was used broadly, but model rearrangement method was noticed lesser for the complex coupling relationship between the structural model and sound field when was studied in-depth, it was regarded as an assistant method. The in-depth study must be developed on the discussion of coupling between structure and sound field in order to get more perfect control results with less sensors/actuators when control energy is limited.Below the critical frequency, the study of sensors/actuators scheme is still enough when carry out the control of sound radiation from structure. The location of Strain patches was devoid of the sound field attribute when a small quantity of patched was used, sensor/actuator scheme study for acoustic radiation control of intelligent plate was carried out in this article, based on the theory of structure-sound coupling, Qualitative analysis on the location of piezoelectric sensors and actuators is given when controlling the sound radiation form panel below the critical frequency, the relationship between structural mode ,sound poles and sound radiation power is deduced, the piezoelectric sensors/actuators scheme was proposed which incarnate the combination of model control method and model rearrangement method, then based on the numerical computation method of FE/BE, Quantitative analysis of the control result of sound radiation is done according to sensors/actuators scheme put forward above, then the contrast was given between The disposal scheme of piezoelectric patches in this article and the scheme based on model control theory in the band of lower frequency. The proposed model on piezoelectric patches location can be used for designing and predicting the control of structural acoustic radiation.