Parametric resonance of a nonlinear energy harvester for torsional vibrations

Torsional vibrations occur commonly in power transmission systems and components. Often these vibrations are subject to transient frequency response, which are nevertheless dominated by fixed multiples of the main shaft speed (such as engine order vibrations). In this paper, a lightweight electromagnetic oscillator is proposed as an energy harvester from these torsional vibrations. A nonlinear spring is applied to tune the response of the oscillator to parametric excitations. Numerical analysis is carried out to predict output power of the harvester over a wide range of frequencies. The dynamics of the system offers the potential of increasing the effective operation band of the harvester, employing parametric resonance.