Design and analysis of a Y-shaped magnetically self-coupled piezoelectric energy harvester

This paper proposes a Y-shaped bifurcated beam magnetic self-coupled piezoelectric energy harvester (Y-MSPEH). By incorporating built-in permanent magnets, the harvester is capable of nonlinear stiffness adjustment and broadband energy harvesting, which in turn helps reduce its physical footprint. To this end, a dynamic model of the Y-MSPEH is developed based on Hamilton’s principle, with geometric nonlinearity and piezoelectric coupling effects taken into account. The study derives numerical solutions for the system response through theoretical analysis and validates them via experiments. For the Y-MSPEH, key parameters, including the magnet’s terminal length, branch angle, and magnetic field strength, are analyzed under both repulsive and attractive magnetically self-coupled states. The results show that adjusting the parameters of the Y-MSPEH can effectively tune the peak frequency of the output voltage response and broaden the response frequency band. Comparative studies indicate that the attractive and repulsive magnetically self-coupled states result in wider response bandwidth and higher response amplitude, respectively. Specifically, compared with the linear Y-shaped bifurcated beam harvester and the geometrically nonlinear Y-shaped bifurcated beam harvester, the Y-MSPEH achieves an approximately 8.26% increase in effective bandwidth in the magnetically self-coupled attractive state, thus demonstrating superior energy harvesting performance.