Wind velocity driven mode transition based piezoelectric energy harvesting utilizing fork-shaped configuration

Abstract

This study proposes a novel fork-shaped piezoelectric galloping-based energy harvester featuring multi-modal vibration characteristics, which can adaptively switch between the first two vibration modes in response to variations in incoming wind velocity. The side beams of the fork-shaped structure are specially connected to the central beam through a connecting plate, enabling independent motion under transverse aerodynamic loads. A distributed-parameter aero-electro-mechanical coupled model, taking into account the rotational motion of the bluff bodies, is established based on the extended Hamilton’s principle and quasi-steady hypothesis. Systematic analysis of in-phase and out-of-phase modal characteristics via the theoretical model reveals that the proposed structure exhibits a remarkably low critical wind velocity of 0.4 m/s. Wind tunnel experiments demonstrate that as wind velocity increases, the structure undergoes an adaptive mode transition from the first-mode-dominated to the second-mode-dominated response. Benefiting from this adaptive mode transition at high wind velocities, the proposed system achieves excellent output performance, with the overall average output power increased by 49.61% compared to an array of two galloping-based piezoelectric energy harvesters. Overall, this study provides new insights and theoretical guidance for enhancing multi-modal energy harvesting capacity over a broad wind velocity range.