Affiliations: [a] Deparment of Mechanics, Tianjin University, Tianjin, China | [b] Tianjin Key Laboratory of Nonlinear Dynamics and Chaos Control, Tianjin, China
Abstract: A type of giant magnetostrictive-piezoelectric composite
vibration energy harvester is proposed in this paper, and its stochastic
nonlinear dynamic characteristics are studied. Giant magnetostrictive
material is applied to induce the harvester's self-excited vibration to
improve its efficiency. Nonlinear differential term is introduced to explain
the hysteresis phenomena of a giant magnetostrictive material, and the
fitting effect of the constitutive model on experimental data is proved by
the partial least-square regression method. The nonlinear dynamic model of a
giant magnetostrictive-piezoelectric vibration energy harvester subjected to
stochastic foundational excitation is developed, and the stationary
probability density function of the system's response is obtained. The
transition sets of the system's response are determined, and the conditions
of stochastic bifurcation are obtained. Numerical and experimental results
show that the stochastic Hopf bifurcation occurs when the parameters varies;
the output voltage is quasi-periodic, which means the effective utilization
to the environmental stochastic excitation.
