Adaptive piezoelectric shunt damping

Piezoelectric shunt damping systems reduce structural vibration by shunting an attached piezoelectric transducer with an electrical impedance. Current impedance designs result in a coupled electrical resonance at the target modal frequencies. In practical situations, variation in structural load or environmental conditions can result in significant changes in the structural resonance frequencies. This variation can severely reduce shunt damping performance as the electrical impedance remains tuned to the nominal resonance frequencies. This paper introduces a method for online adaptation of the shunting impedance. A reconstructed estimate of the RMS strain is minimized by varying the component values of a synthetic shunt damping circuit. The techniques presented are applied in real time to tune the component values of a randomly excited beam.