A parametrically broadband nonlinear energy harvester
In this work, for the first time, an energy harvester based on the nonlinear dynamical response of a parametrically excited cantilever beam in contact with mechanical stoppers has been fabricated and tested; a 145% increase in the bandwidth at which energy can be effectively harvested has been observed. Experimental and theoretical investigations have been performed in order to assess the increased operating bandwidth of the energy harvester fabricated; for the experimental investigations, an electrodynamic shaker connected to a shaking table has been used to parametrically stimulate the energy harvesting device. Results showed that the parametric energy harvester without stoppers displayed a weak softening-type nonlinear response; however, with the addition of mechanical stoppers the energy harvester displayed a strong hardening-type nonlinear response which is ideal for capturing kinetic energy over larger bandwidths. The addition of mechanical stoppers on a parametrically excited cantilever beam has significant qualitative and quantitative effects on the nonlinear parametric energy harvesting; the energy harvesting bandwidth was increased in the range of 35-145% by adjusting the stoppers.