Experimental Investigation on the Chaos-to-Interwell Motion Transfer in a Bistable Beam-Slider Vibration Energy Harvester

Bistable structures are widely used for vibration energy harvesting due to their wide bandwidths and extraordinary performance. However, the dynamics of bistable structures are complicated, and inter-well, intra-well, chaotic, superharmonic, and subharmonic vibrations may coexist in some frequency ranges. Inter-well vibration is typically the most desired because of its large oscillation amplitude, which means more kinetic energy can be converted into electricity via different energy transduction mechanisms. In this study, a modified bistable beam-slider vibration energy harvester consisting of a cantilever beam and a movable slider on the beam is investigated experimentally. The slider can move along the beam under the combined effect of the inertial and magnetic forces. Moreover, magnetic nonlinearity is incorporated into the beam to achieve bistability instead of the linear or monostable configurations typically found in existing literature studies. The slider trajectory and the bistable cantilever beam time responses show that the slider can help the bistable beam system transfer from the chaotic to the inter-well vibration orbit. The results show that inter-well vibration can be maintained even with disturbance introduced with 3.92 m/s(2) base excitation over the 15 Hz-18 Hz frequency range. The whole transfer process is self-regulating and does not require any external intervention. Therefore, the harvester we designed is self-adaptive, with a substantially broadened operating bandwidth.