Dynamic responses of a two-degree-of-freedom bistable electromagnetic energy harvester under filtered band-limited stochastic excitation

Abstract

This study investigates the dynamic responses of a two-degree-of-freedom (2DOF) nonlinear bistable electromagnetic energy harvester under filtered band-limited stochastic excitation. The mathematical model of the 2DOF bistable energy harvester is derived, and its fidelity is experimentally verified. A comprehensive numerical investigation is conducted under filtered band-limited stochastic excitation (which is the white Gaussian noise filtered by a second-order filter). Comparative studies are performed between the 2DOF bistable energy harvester, the 2DOF equivalent linear energy harvester, and the single-degree-of-freedom (SDOF) linear energy harvester when subjected to white Gaussian noise and the exampled band-limited stochastic excitation. The comparative results show that the 2DOF bistable energy harvester can significantly improve the average power compared to the equivalent 2DOF and SDOF linear energy harvesters. The study reveals the insights of the excitation strength, bandwidth, and center frequency into the system performance. Finally, structural parametric studies demonstrate that the bigger frame mass and the larger spring stiffness coefficient will increase the oscillation velocity which has great significance for energy harvester.