Nonlinear dynamics and performance enhancement of multi-stable wideband energy harvesting : theoretical analysis

Abstract

A new multi-stable wideband harvester is proposed to increase the power density of energy harvesting under wide-bandwidth and low-frequency operations. This harvester can possess with an arbitrary multi-stable state by combining the nonlinearities of stopper-engaged cantilevers and magnetic forces. The harvesting efficiency can be enhanced by interwell oscillations and the global amplitude of the harvester is restricted by the cantilever-stopper engagement. An electromechanical coupling model of the proposed harvester is established to describe its dynamic characteristics. To explore the influence of potential well configurations on a multi-stable energy harvesting, the proposed harvester with four typical potential well configurations is considered while its equivalent nonlinear restoring force can be experimentally identified. The dynamic characteristics of these four configurations at different levels of a harmonic excitation will be explored by both numerical and experimental methods. It is expected that a multiple-well potential with non-uniform depths and shallower outer wells is much more suitable for the proposed system when the external excitation exceeds a critical intensity.