Stochastic Analysis of a Hybrid Energy Harvester with Viscoelastic Material

The hybrid energy conversion mechanism can improve the performance of the energy harvester compared to the single energy conversion mechanism. Meanwhile, the use of viscoelastic materials can also improve the energy harvesting efficiency, but there is not much research on hybrid energy harvesting systems with viscoelastic material. Different from existing research, this manuscript investigates the probabilistic response and stochastic bifurcation of a hybrid piezoelectric and electromagnetic energy harvester(HPEEH) with viscoelastic term under random excitation. Firstly, the viscoelastic element is approximately equivalent to the linear combination of damping term and stiffness term through variable transformation. Secondly, the accuracy of the proposed method is verified by comparing the numerical solution with the analytical solution using the stochastic averaging technique to solve the equivalent system. Furthermore, the bifurcation conditions for amplitude steady-state probability density are given according to the singularity theory and the definition of the extreme point. It is found that changes in viscoelastic parameters, damping coefficients and electromagnetic coupling coefficients can induce stochastic P-bifurcation. Finally, the effects of system parameters on mean square current, mean square voltage and mean output power are explored.