Analytical and experimental study on vibration energy harvesting behaviors of piezoelectric cantilevers with different geometries

Power supply is a bottle-neck problem of wireless micro-sensors, especially where the replacement of batteries is impossible or inconvenient. Now piezoelectric material is being used to harvest vibration energy for self-powered sensors. However, the geometry of a piezoelectric cantilever beam will greatly affects its vibration energy harvesting ability. So in this paper strain formulation of rectangular, trapezoidal and triangular piezoelectric cantilevers are deduced respectively. Then their finite element models and static analysis are presented by a finite element analysis method. Simulation and experiment results demonstrate that under the same conditions using triangular cantilever beams can improve the strain distribution and generate more voltage than trapezoidal and rectangular. Thus the proposed method will provide theoretical principles of optimal designing piezoelectric cantilever beams for vibration energy harvesting to power wireless micro-sensors.