Investigation on the energy trapping and conversion performances of a multi-stable vibration absorber

Abstract

Multi-stable energy harvesters have emerged as the most attractive candidates for vibration-based energy harvesting recently. Energy trapping and energy conversion are the main characteristics of a vibration-based energy harvester, similarly, energy absorption and damping dissipation are the main features of a conventional dynamic vibration absorber (DVA). Therefore, combination of vibration absorption and energy conversion is a potential strategy for vibration control and self-powered wireless sensors. This paper presents the principle design of tri-stable systems and mathematical modeling of a 2-dof tri-stable DVA and energy harvester. The energy harvesting performances of multi-stable energy harvesters in terms of tri-stable electromagnetic energy harvester (TEEH) and bi-stable electromagnetic energy harvester (BEEH) are evaluated under impulsive excitations and harmonic vibrations, respectively. The energy trapping capacity of TEEH is calculated under single impulsive excitation and compared with its counterpart of BEEH. Furthermore, the dynamic characteristics of the multi-stable DVA (tri-stable and bi-stable) are studied. Simulation results show that TEEH induces a more rapid attenuation in the residual kinetic energy of the primary system excited by a weak impulse than its counterpart of BEEH, and the trapped energy in TEEH increases remarkably with the application of a weak impulse. Compared with BEEH, the energy dissipation and harvesting performances of TEEH are more satisfactory under low-amplitude impulse and low mass ratio conditions. Additionally, the snap-through motion can be more easily triggered in TEEH under broadband and low-amplitude vibrations. With the increase in vibration amplitude, the multi-stable mechanism of TEEH can be readily understood through observing phase portrait and Poincaré mapping, from which tri-stable state, chaotic attractors and bi-stable state are presented successively. Moreover, the energy harvesting efficiency of TEEH is more advanced under broadband ambient vibrations in comparison with BEEH. Finally, a prototype of tunable tri-stable system composed of a linear spring and magnetic spring is proposed.