Danila Meimukhin

Lecturer:              Danila Meimukhin

Supervisor:          Prof. Izhak Bucher

Title:              On the advantage and optimization of a bi-stable energy harvesting oscillator under band-limited stochastic excitation

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.

Experimental setup,  snap through jumps,  slow motion video – 300 fps.

Experimental setup – CAD design


Experimental setup – top view

CAD section view of the seismic tip of the cantilever. Array of magnets forming magnetic flux through two coils.

Magneto-static force from Ansys analysis.

Magneto-static potential from Ansys analysis.

Power as function of input power and distance between the wells