Study of a tuned vibration absorber using piezoelectric patches with active shunt circuits

Abstract

A patch of piezoelectric material driving a negative impedance shunt circuit can be attached to a flexible structure for vibration damping as well as altering the effective stiffness of the overall structure and shift its resonant frequency. This work uses a truly coupled mechanical/electrical analysis where the negative impedance converter (NIC) circuit is modeled using fundamental operational analysis modeling technique, enabling a straightforward analysis of circuit stability, while clarifying the effect of each parameter in the NIC circuit on the overall circuit impedance, and ultimately, the mechanical response of the structure. Two types of piezoelectric materials are considered, a piezoelectric polymer and a macrofiber composite. Also examined in this work is an alternative approach to load impedance tuning which seeks circuit parameter settings that equate the load impedance to the complex conjugate of the mechanical impedance of the piezoelectric for a particular out-of-plane vibration mode. Additionally, the effects of circuit stability and variations of the reference capacitor are investigated. Both theoretical simulations and experimental results are presented.