Investigating the Effects of Geometrical Parameters on the Performance of Piezoelectric Energy Harvesters under Harmonic Base Vibration Using Analytical and Finite Element Modeling

In this paper, energy harvesting from base vibration of cantilever beam is considered.With taking into account the high electromechanical coupling of piezoelectric materials in comparison to other vibration energy harvesting methods, the considered structure of energy harvester is a three layers beam that consists of one metal substrate layer and two piezoelectric layers at up and down of it and a proof mass at free end.The considered harvester is modeled in ANSYS finite element software using CPC-FEM technique and effects of geometrical parameters of energy harvester on mechanical and electrical behavior of it are investigated. The optimized dimensions of harvester by using genetic algorithm (GA) are presented and the achieved results from CPC-FEM technique are compared with analytical method counterparts. Results indicate that finite element and analytical methods have an acceptable adaptation. But, because of considering the stress strain relation at whole of beam length with electrode, finite element method presents the accurate results. Also, results show that piezoelectric energy harvester can harvest 4.4 mW power and 9.3 Vvoltage at optimum electrical resistance of 10kohm that is sufficient to power sensor nodes and other low consumer electronic equipments.