Coherence resonance of a magnet-induced buckled piezoelectric energy harvester under stochastic parametric excitation

This study takes the magnet-induced buckled piezoelectric energy harvester as the object of research and employs the stochastic Melnikov method to explore the necessary conditions for occurrence of coherence resonance. The magnet-induced buckled piezoelectric energy harvester configuration is composed of a clamped–clamped beam, with one movable end subjected to an axial stochastic magnetic acting force. The model’s stochastic Melnikov function is derived and then the necessary conditions for coherence resonance are obtained. The analyses reveal that the magnet’s distance and the proof mass may influence the threshold of inter-well motion significantly. Numerical simulations are carried out, and Kramers rate is applied to prove the analytical predictions. A harvester prototype was fabricated, and the corresponding experiments were carried out for validation. The results proved the theoretical analyses and the simulation results. The influences of stochastic excitation level and magnet separation distance on the performance are thoroughly discussed. The results provide a guideline for design and optimization of the magnet-induced buckled piezoelectric energy harvester.