An Arch-Linear Composed Beam Piezoelectric Energy Harvester with Magnetic Coupling: Design, Modeling and Dynamic Analysis

A novel bistable piezoelectric energy harvester (BPEHC) is constructed by introducing a nonlinear magnetic force on an arch-linear composed beam. The nonlinear magnetic model is obtained by using equivalent magnetizing current method, and the nonlinear restoring force model of the arch-linear composed beam is acquired based on fitting experimental data. The corresponding coupled governing equations are derived by using generalized Hamilton principle. The dynamic responses are obtained by solving the coupling equations with the ode45 method, and the effect mechanism of the excitation frequency and amplitude on large-amplitude periodic response is discussed and analyzed via the bifurcation diagram, the maximum Lyapunov exponent diagram, and the Poincaré map. Moreover, the correctness of the theoretical analyses is qualitatively verified by experiments. The results reveal that the threshold excitation amplitude for the system to realize large-amplitude interwell oscillation is increased with the increasing of the excitation frequency, if the system starts with appropriate excitation level, it can do large-amplitude interwell oscillations at low excitation frequency. Compared with the non-magnet energy harvester, the BPEHC has much better energy harvesting performance owing to the nonlinear magnetic force being efficiently introduced to broaden bandwidth. The arch-linear composed beam is superior to the conventional straight beam in enhancing output voltage and power. Overall, introducing the arch-linear composed beam into the bistable piezoelectric energy harvesting system contributes to enhance power output, improve energy harvesting performance of the piezoelectric energy harvester.