A Novel Quasi-Zero-Stiffness Energy Harvester with Surface Constraints for Ultralow Frequency, Ultralow Amplitude and Wide Band Excitation

Energy harvesting from external vibration under ultralow frequency, ultralow amplitude and wide band excitation has received extensive attention in recent decades. A novel quasi-zero-stiffness energy harvester based on cantilever beam with surface constrains (QZS-EHSC) is proposed and its harvesting performance is analyzed in this study.

The quasi-zero-stiffness (QZS) characteristic can generate large-amplitude motions under low frequency excitation. The surface constraints are beneficial to broaden the frequency band and generate large strain even far away from the beam root, which can improve the harvesting efficiency. Considering the magnetic interaction between the magnet at the tip of a cantilever beam and two fixed magnets, it can realize a multi-stable structure. The static analysis reveals that the QZS-EHSC system can achieve multi-stable state by adjusting parameters, which is beneficial for energy harvesting. The experiments verified the advantage of QZS-EHSC on harvesting power.

The system can generate large-amplitude motions at ultralow frequency and ultralow amplitude excitation (0.2 Hz, 0.2 g) by selecting appropriate parameters. Under the same excitation, the frequency range of inter-well period-1 motions is about 1.50 times that of non-QZS-EHSC, greatly improving the harvesting efficiency.

QZS-EHSC is a feasible design for harvesting energy from ultralow frequency, ultralow amplitude and wide band excitation.