Active Control of Structural Acoustic Radiation via Eigenvector Assignment Techniques

摘要

The objective of this research is to investigate the feasibility of utilizing eigenvector assignment techniques to reduce structural acoustical radiations of a smart panel. The structural sound pressure can be expressed in terms of a combination of vibration modes, where its magnitude is also a function of the external disturbance distribution. In other words, the radiated sound pressure level depends on both the right eigenvectors (related to the structural mode shapes) and left eigenvectors (related to the system disturbance rejection ability) of the vibrating structure. The basic idea of the proposed approach is to simultaneously modify the mode shapes and disturbance rejection ability of the smart structure through active action of piezoelectric actuators, so that the sound pressure radiated from the vibrating structure can be reduced. Numerical simulations are performed to evaluate the effectiveness of the proposed method on structural noise reduction. Frequency response of sound pressure at receivers in the selected frequency range is illustrated. It is shown that with active piezoelectric actions, the proposed method can re-shape modal velocity distribution and enhance disturbance rejection, and hence can effectively minimize the structural sound pressure radiation.