Theoretical modeling and nonlinear analysis of piezoelectric energy harvesters with different stoppers

Abstract This study focuses on investigating the dynamic mechanism and nonlinear analysis of a piezoelectric energy harvester with different stoppers so as to determine optimal impact energy harvesting configurations. Based on the Hamilton's principle, a set of coupled nonlinear governing equations for the energy harvesting system is established, which is then discretized by the Galerkin method. It is indicated that the energy harvester without stoppers displays a softening characteristic and this softening becomes more obvious with increasing the base acceleration. This is due to the considered geometric and inertia nonlinearities. By introducing stoppers to the harvester, however, the dynamic behavior changes from softening to hardening characteristic, owing to the induced impact force nonlinearity. Then four kinds of stoppers are compared and better stopper configurations for energy harvesting performance are picked out, following by the consideration of parametric analysis on stopper's stiffness, placed position and spacing distance. It is noted that there exists optimal parameter regions where the energy harvester can strike a balance between bandwidth and generated average power depending on excitation frequencies in surroundings.