Theoretical and experimental investigations of multibifurcated piezoelectric energy harvesters with coupled bending and torsional vibrations

This paper investigates a multibifurcated piezoelectric energy harvester (MBPEH) with coupled bending and torsional vibrations to enhance energy harvesting performance. A theoretical model is established and verified by the finite element method (FEM) and experimental results. The results show that the theoretical results show good performance with the FEM and experiments in both the output amplitude and response frequency bands. In addition, the multimodal response mechanism of the MBPEH is revealed. The influence of the bifurcated angle and the length of the bifurcated beams on the energy harvesting performance are deeply analyzed. Furthermore, it is revealed that the asymmetry of the bifurcated beams is conducive to energy harvesting. The Y-shaped (two bifurcated beams) MBPEH works in bending and axial mode (BAM), and bending and torsional mode (BTM) are compared, and the results show that the Y-shaped BTM-MBPEH has a better energy harvesting performance in medium-frequency and low-frequency bands.