Abstract
In recent years, there has been considerable interest in developing piezoelectric cantilevers for energy harvesting. Most cantilever-based harvesters are difficult to adapt to the multi-directionally complex vibration environments because of its unidirectional, which results in the dissipation of the multi-directional energy source and cannot be effectively harvested. This article proposes a cantilever-asymmetric-pendulum combined structure that is formed by a flexible cantilever beam and an asymmetrically conical pendulum with a rigid thin rod and two different concentrated end masses. With the nonlinear coupling between the motion of asymmetric pendulum in 3-dimentional space and the vibration of beam bending, 1:2 internal resonance is induced to enable that the multi-directionally vibration can be delivered to unidirectional cantilever bending, for effectively harvesting vibratory energy of excitations from an arbitrary direction. Lagrange’s equations are utilized to establish mathematical models of the combined structure, and numerical simulation is carried out to analyze the characteristics of systems responses under x-direction excitations and z-direction excitations. Simulation results verify that, with internal resonances, the cantilever-asymmetric-pendulum system responses optimally under excitations around both the asymmetric pendulum natural frequency and the complete system natural frequency.
