Dynamics and performance of a two degree-of-freedom galloping-based piezoelectric energy harvester

To improve the performance of the galloping based piezoelectric energy harvester (GEPH), this paper analytically investigates the potential advantages of the 2-degree-of-freedom (2-DOF) GPEHs over the conventional 1-DOF GPEH. Firstly, two different configurations of 2-DOF GPEH are proposed and the corresponding governing equations are presented. The approximate analytical solutions to both configurations are derived by using the harmonic balance method. Numerical simulations are conducted to verify the accuracy of these analytical solutions. Subsequently, comparisons are conducted between the 1-DOF GPEH and the 2-DOF GPEHs in terms of the cut-in wind speeds and output powers. It is demonstrated, both analytically and numerically, that the second configuration of 2-DOF GPEH can easily and remarkably reduce the cut-in wind speed and improve the output power from galloping phenomenon. Finally, a parametric study is performed to ascertain the effects of the mechanical parameters of the second configuration on the energy harvesting performance. Based on the results from the parametric study, design guidelines for tuning the mechanical parameters are provided to achieve performance enhancement.