A new framework of piezoelectric smart tiles based on magnetic plucking, mechanical impact, and mechanical vibration force mechanisms for electrical energy harvesting

Abstract

In this paper, a new framework based on combining three different mechanisms is proposed to improve electrical energy harvesting from piezoelectric smart tiles. These mechanisms are named magnetic plucking (MP), mechanical impact (MI), and mechanical vibration force (MVF). The MP mechanism uses the magnetic interaction between an iron rod and a magnet to excite the consoles used in the tile. In the MI mechanism, the piezoelectric cells are stimulated by the mechanical function of the cantilevers. Also, in the MVF mechanism, piezoelectric cells are stimulated by the cantilever oscillations of MP and MI. In the experimental design procedure of the proposed smart tile structure, at first, the smart tile based on consoles made of MP, MI, and MVF mechanisms are designed. Then, to compare the electrical energy harvesting of the proposed structure with other tiles, the proposed smart tile with 36 piezoelectric consoles, which is a combination of three mechanisms, is implemented. To protect the piezoelectric cells against excessive bending during the operation of the consoles, the swing of the consoles is limited by using a plastic stopper. The proper air gap between the magnet and the iron rod as well as the air gap between the console and the stoper are determined by actual tests. In the energy harvesting evaluations of the proposed structure, the energy and average power of 71.0 mJ and 13.6 mW were obtained at the optimal resistance load of 100 kΩ. Experiments on energy harvesting from tiles made of MP, MI, and MVF mechanisms were also conducted. When comparing the electrical energy harvested from the proposed framework, utilizing rectification with the diode bridge and capacitor filter, with that generated by the MP, MI, and MVF mechanisms, a substantial increase in energy yield was observed. Also, the average energy harvesting time of the proposed structure has increased by 59.4 % compared to the other three mechanisms.