Design and experimental verification of torsion-bending low-frequency piezoelectric energy harvesters

We design and experimentally validate a zigzag piezoelectric energy harvester that can generate energy at low frequencies and which can be used to operate low-power consumption electronic devices. The harvester is composed of metal and piezoelectric layers and is used to harvest energy through direct excitations. A computational model is developed using Abaqus to determine the exact mode shapes and coupled frequencies of the considered energy harvester in order to design a broadband torsion-bending mechanical system. Analysis is then performed to determine the optimal load resistance. The computational results are compared and validated with the experimental measurements. More detailed analysis is then carried out to investigate the effects of the masses on the bending and torsion natural frequencies of the harvester and generated power levels. The results show that due to the coupling between the bending and torsion modes of the zigzag structure, highest levels of the harvested power are obtained when the excitation frequency matches the coupled frequency of torsion type for three different values of the tip mass.