Variable- Potential Bistable Nonlinear Energy Sink Coupled with Electromagnetic Harvesters for Enhanced Vibration Suppression and Energy Harvesting

Abstract

Although bistable technology has been proven to be effective in the fields of vibration suppression and energy harvesting. However, the simultaneous realization of high-efficiency, broadband vibration absorption and harvesting of bistable nonlinear energy sink (BNES) with a predetermined fixed-potential barrier at unknown or ultra-low energy level excitation is still an open issue. To address this challenge, we propose a variable-potential bistable nonlinear energy sink coupled electromagnetic harvesters (VBNES-EH) to outperform the conventional BNES or bistable energy harvester (BEH). Its performance in the ultra-low and broadband input energy range is enhanced by introducing a horizontal energy harvester (HEH) to dynamically reduce the potential barrier height of the BEH and the threshold for exciting chaotic or strong modulated responses. First, a dimensionless mathematical model of the VBNES-EH is proposed. The transient dynamics and corresponding energy dissipation rates of five target energy transfer mechanisms for the weakly damped system are summarized numerically. The bistable stiffness softening effect and its benefits for the dual functions of vibration suppression and energy harvesting are analyzed. Comparing the damped transient responses of the VBNES-EH and conventional BNES indicate that the former has better performance, no matter at low, intermediate, or high energy level impact excitation. Furthermore, the influence of system parameters on the energy harvesting efficiency is detailed to guide designing the optimal performance. Finally, the performance improvement, dynamic evolution, and the effect of system parameters on the dual function of the VBNES-EH at harmonic sweep excitation are also investigated. Numerical results demonstrate that the dual performance of the VBNES-EH under harmonic excitation is also better than that of the conventional BNES.

Keywords: Bistable nonlinear energy sink, Bistable energy harvester, Target energy transfer, Variable potential barrier, Strong modulated oscillation