Fully-passive implementation of multi-branch piezoelectric shunts for multimodal vibration damping

Abstract Vibration damping using resonant piezoelectric shunts mitigates the mechanical resonances by coupling an electrical circuit to a structure through a piezoelectric transducer. The classical resonant shunt consists of an inductor that creates an electrical resonance tuned to the frequency of the mode to be controlled. In order to damp several resonances simultaneously, multi-branch shunts are used with multiple electrical lines connecting a single piezoelectric patch. Several multi-branch shunts have been proposed in the literature. In this work focused on passive control, only circuits involving resistors in series with inductors are considered. Only two solutions are thus retained: the Hollkamp shunt and the current blocking shunt. New tuning equations for the electrical components of these shunts are developed, accounting for the parasitic copper losses in the passive inductors as well as the dielectric losses in the piezoelectric patches. The selection of passive inductors is detailed to ensure adequate resistance margins and reduce the size of the magnetic components. Numerical and experimental comparisons are conducted to evaluate the performance in terms of vibration reduction and the influence of additional resistive components. A thorough assessment of copper and dielectric losses demonstrates the capability for broadband passive vibration reduction, delivering effective performance even for systems with complex geometries and low electromechanical coupling factors.