Piezomagnetoelastic energy harvesting from bridge vibrations using bi-stable characteristics

Harvesting energy from bridge vibration is a promising solution to self-powering the wireless sensors that are distributed in the bridge for safety monitoring. In this study, a novel harvester is proposed to scavenge bridge vibration energy caused by travelling vehicles. The harvester employs bi-stable characteristics to enhance the harvesting efficiency, which is realized by magnetic interaction between the tip and fixed magnets. The influences of distance between the magnets on the potential energy and restoring force are studied. The results show that an appropriate distance can give a desired bi-stable potential energy function. The experiment study is carried out. The results prove that the proposed bi-stable harvester could produce a large-amplitude vibration and achieve a significant improvement in vibration energy harvesting. It can keep large electric output for a wide range of vehicle speed. In addition, the bi-stability characteristics from magnetic attraction can protect the harvester from damage while the excitation is excessively large. This study may provide a practical method for efficiently harvesting energy from bridge vibration.