Harmonic Balance in the Dynamic Analysis of Circular Composite Plate Harvester

A piezoelectric energy harvester is investigated with the focus on its nonlinear behavior. The core of the harvester is a circular composite plate. A lumped parameter model of the harvester is established with its parameters identified from the experimental data. A fifth polynomial is employed to approximate the nonlinear restoring force. The harvesting system is theoretically studied by the harmonic balance method with the arc-length continuation and the solutions are supported by the time-domain numerical simulations and experiment results. The results display that the amplitude-frequency response has soft characteristics under small excitations but both hard and soft characteristics under large excitations, which broadens the working bandwidth of the harvester.