Breathing cylindrical piezoelectric energy harvesters

A breathing piezoelectric energy harvester (BPEH) is proposed and evaluated in this paper. A thin cylindrical shell is chosen as the substructure of energy harvester. Based on the Kirchhoff-Love thin shell theory and the direct piezoelectric effect, electro-mechanical coupling mechanism is formulated. An equivalent energy harvester circuit is obtained. It clearly reveals the link between the piezoelectric sensing theory in open circuit and the energy harvesting theory in close circuit. Then, distributed modal power is obtained by using the modal expansion method. To evaluate the effect of model design parameters to energy harvesting, a harmonic excitation, which is able to induce breathing modes, is imposed to the shell model. The optimal equivalent resistance is obtained and it is closely related to the inner impedance of piezoelectric patch. Power generations with respect to the size and location of piezoelectric harvester patch are evaluated, and the optimal location is obtained. All these parametric analysis can be utilized to improve efficient design of piezoelectric energy harvesting.