Structure-Borne Noise Reduction by Active Damping of a Radiating Panel

The effectiveness of positive position feedback (PPF) controllers to selectively damp a particular mode or a cluster of modes is demonstrated by controlling the vibration of a rectangular flexible plate. The modes of vibration of this plate occur in adjacent pairs. The plate is actuated by two patches of piezoelectric PZT actuators at two corners. The strain at the vicinity of each actuator is measured with a PZT sensor mounted in a nearly collocated arrangement with the each actuator. In a series of experiments, PPF controllers were tuned to different single or multiple modes with different damping ratios. The resulting controlled plate had considerable damping in its first four modes of vibration.