Ph.D Thesis


Ph.D StudentDanila Meimukhin
SubjectAnalytical and Experimental Study of an Optimal Bi-Stable
Energy Harvesting Oscillator under Band-Limited
Stochastic Excitation
DepartmentDepartment of Mechanical Engineering
Supervisor Full Professors Bucher Izhak
Full Thesis textFull thesis text - English Version


Abstract

Oscillation-based linear energy harvesters are often excited by random, band-limited, slowly-varying forces. When the excitation bandwidth is limited such that natural frequencies of electromechanical energy harvester are not excited, linear devices lose their efficiency and nonlinear structures with negative stiffness can be ?used to enhance the conversion efficiency by performing frequency up-conversion. It is shown that nonlinear, bistable oscillators perform considerably better than their linear counterpart under band-limited excitation, in certain regions. This is contrary to commonly modeled, wide-band or white noise excitation, where nonlinear potential has no or little effect on the energy output. A sharp increase in performance is observed for band-limited random excitation along a well-defined region in the input-level and bandwidth plane. Given the ambient source of the vibration the shape of the potential is of the particular interest, as by controlling the distance between the stable points, the power output can be increased. The corresponding study is based on partially analytical, numerical and experimental analysis of the dynamical system containing array of permanent magnets and cantilever beam.