Bursting oscillation and its mechanism of the flow-induced vibration piezoelectric energy harvester with magnets by low-frequency excitation

The purpose of this paper is to study the bursting oscillation and its mechanism of the flow-induced vibration piezoelectric energy harvester with magnets (PEHM) by low-frequency excitation. Through the slow-fast analysis method, the external excitation term is considered as the slow variable, which is the control parameter to regulate the nonlinear dynamic behavior of the fast subsystem. The time history, phase and transformed phase diagrams of the PEHM system in three cases when the bursting oscillation occurs are obtained. The motion law and bifurcation mechanism are then revealed. Next, the chaotic motion of the system is observed by the maximum Lyapunov exponent graphs, and the influence of the excitation frequency on the periodic motion is studied via.-x bifurcation diagrams. Afterwards, the influence of the excitation amplitude and cantilever beam equivalent damping ratio on the output voltage in bursting state is analyzed. Taking the average output voltage value as a measurement index, in consideration of the variations of the output power with load resistance, we also evaluate the influences of external excitation amplitude and frequency on the energy harvesting efficiency. The results show that the increase of the excitation amplitude can widen the frequency band of high energy harvesting efficiency; The excitation frequency close to bursting frequency leads to large output power in an instant. Finally, the influence of the potential energy function and the barrier height on bursting oscillation are investigated.