Analytical and experimental study of a clamped-clamped, bistable buckled beam low-frequency PVDF vibration energy harvester

Abstract

Vibration-based energy harvesting devices have drawn interest as a potential low-maintenance power source for a variety of applications, such as for systems involving distributed networks of remote sensors. In this work, an energy harvesting system is considered that is based on bistable, buckled beams and the flexible piezoelectric polymer polyvinylidene fluoride (PVDF). The stability and dynamic response of the structure under vibration loading is modeled, and the resulting output voltage is analytically predicted. Modeling outputs are compared with experimental results for driving frequencies below 30 Hz, the range for many common vibration energy harvesting environments. The modeling approach used in this work is based on coupled electrical-mechanical equations of motion for a geometrically nonlinear Euler-Bernoulli piezoelectric beam that were developed via Hamilton's principle. A component sectioning procedure was used in conjunction with implementation of matching conditions at the boundaries to solve for the nonlinear static and linearized dynamic structural equations. These gave both the buckling and dynamic shape functions, which were used as a basis for finding the device nonlinear dynamic response. Several parameters including vibrational motion, output voltage, and frequency response were analyzed both theoretically and experimentally under different driving conditions. Good agreement was found between the developed model and the experiments, particularly with respect to predicted regimes of behavior and power output. The results suggest that the proposed modeling approach could be successfully implemented in the design and analysis of other multi-component piezoelectric-based energy harvesting systems.