Opportunities for using non-linear oscillators to enhance energy harvesting from impulsively loaded structures

In this study, opportunities of using non-linear oscillators for enhanced energy-harvesting performance are explored. Non-linear systems involving a linear impulsively loaded structure, denoted as the source, and a non-linear oscillator, denoted as the harvester, are considered. An approximate method with complex representation is used to analyse the behaviour of the harvester. Energy harvested is assumed to be converted to electricity through electromagnetic induction and dissipated on resistive load. Thus, the electromechanical coupling is modelled with equivalent viscous damping. It is found that there is a generalized resonant condition under which the harvester absorbs significant amounts of energy from the source. It is shown that as a special case of the generalized non-linear resonance, linear resonance sets the upper bound performance while, when there is significant frequency mismatch, a device designed with proper non-linearity may harvest more energy than its linear counterpart.