Dynamics of the double-beam piezo-magneto-elastic nonlinear wind energy harvester exhibiting galloping-based vibration

This paper investigates a dynamic model and behavior of a novel double-beam piezo-magneto-elastic nonlinear wind energy harvester (DBPME-WEH). The DBPME-WEH is a double-beam structure, which contains the magnet-induced bistable nonlinearity to enhance the performance of the galloping-based vibration energy harvesting. The corresponding governing equations of motion are formulated, and the numerical results based on the equations are validated by a series of the wind tunnel experiments. Both the numerical and experimental results show that the DBPME-WEH outperforms the linear double-beam piezoelectric wind energy harvester, significantly reducing the cut-in speed. To understand the nonlinear dynamic behavior of the proposed energy harvester, this study performs the numerical investigations of the time-domain responses, phase portraits and frequency spectrums of the DBPME-WEH under selected wind speeds. The intra-well, chaotic and inter-well oscillations are discovered with respect to low, medium and high wind speeds intervals, respectively. The parametric study is performed to uncover the influences of the beams stiffness ratio, effective mass ratio and the width of the bluff body that help developing the insights of the effective design of the DBPME-WEH.