Design and analysis of an extended buckled beam piezoelectric energy harvester subjected to different axial preload

In this paper, a piezoelectric energy harvester composed of a buckled beam and an extended beam with a tip mass is proposed. This study develops a mathematical model and a prototype of the energy harvester. The performance of the energy harvester is influenced by the axial load applied at the end of the buckled beam. Under an axial force below the critical load, the energy harvester exhibits a pre-buckling state with a hardening nonlinear characteristic. Conversely, when the axial force exceeds the critical load, a post-buckling state with a softening nonlinear characteristic is observed. Simulation results are validated through experiments, and the relationship between axial displacement and axial force is obtained through experimental data. Moreover, increasing the tip mass enhances the output voltage under the same acceleration. The energy harvester demonstrates superior performance in terms of output power and strain distribution compared to a cantilever counterpart.