Piezoelectric Energy Harvester With a Mass-Spring Oscillator Under Vortex-Induced Vibrations

Abstract This study presents the design, modeling, and experimental validation of a vortex-induced vibration (VIV)-based piezoelectric energy harvester integrated with a mass-spring oscillator. The novelty of the design lies in the inclusion of an auxiliary oscillator at variable positions along the cantilever beam, introducing additional degrees-of-freedom to expand the operational bandwidth. A dimensionless coupled electromechanical model was developed using Euler–Bernoulli beam theory and a Van der Pol-based wake oscillator and validated against wind tunnel experiments. The results confirm that the oscillator modifies the harvester dynamics, converting a single narrow lock-in region into two distinct regions, thereby enhancing the power bandwidth. The dimensionless analysis demonstrates that positioning the oscillator toward the free end (s≥0.5) and selecting a moderate ratio of oscillator stiffness to total harvester stiffness (0.10≤ks≤0.22) consistently produces two distinct lock-in regions and significantly broadens the operational bandwidth. An optimization procedure further identified configurations that balance power output at each lock-in region and bandwidth extension. The findings demonstrate that oscillator-beam coupling offers a practical route to achieving tunable, broadband performance in piezoelectric VIV harvesters, with potential applications in powering low-energy autonomous sensors.