67 / 2021-03-29 16:50:41

Dynamics of a tri-stable energy harvester under narrow-band random excitation

narrow-band random excitation; tri-stable piezoelectric energy harvester; multiple scale method; harvesting performance

Abstract: Vibration energy harvesters convert mechanical vibration energy into electrical energy, which can be divided into linear and nonlinear energy harvesters. However, the resonance frequency band of the linear piezoelectric energy harvester is often narrow, and it is difficult to match the wide frequency of the environmental vibration and achieve high power generation efficiency. In particular, the tri-stable model with three potential wells and two potential barriers has outstanding advantages in improving the broadband performance of energy harvesting or enhancing the detection effect of weak signals. This paper investigates a tri-stable energy harvester under narrow-band random excitation by using Hamilton type generalized variational principle to establish electro-mechanical coupling equation of motion. The analytical solution of this equation is obtained through the multiple scale method. Meanwhile, the effects of system parameters, such as noise intensity, piezoelectric coupling, distance between magnets and the acceleration amplitude of excitation are explored by Monte Carlo simulations. The results of theory and simulation are verified by designing an experiment, which proves that the energy harvesting efficiency of tri-stable energy harvester under narrow-band random excitation can be improved by optimization of nonlinear stiffness parameter.