Reductionof noise inside a cavity by piezoelectric actuators

摘要

A new analytical model is developed for the reduction of noise inside a cavity using distributed piezoelectric actuators. The cavity is modeled with four rigid walls and two flexible panels, panel on the top is excited by disturbing point forces and thus radiating structure borne noise into the cavity,and the other panel which is on the bottom is bonded with actuators to control the noise inside the cavity. Modal coupling method is used to establish the governing equations of motion of the fully coupled acoustics-structure-piezoelectric patch syste. Two performance functions relating 'global' and 'local' optimal control of sound pressure levels (SPL) respectively are applied to obtain the control laws. Numerical investigations into the effect of number of actuators, error sensors as well as disturbing point forces on SPL's are presented. Based on the studies, it is found that the number of actuators has a significant influence on SPL's for local control case, while for global control case, this influence is quite limited. The discussionson associated control mechanism show that both the mechanisms of modal amplitude suppression and modal rearrangement may sometimes coexist in the implementation of optimal noise control.