A V-shaped galloping piezoelectric energy harvester exploiting bending and torsional modes

Traditional straight beam galloping-based energy harvesters can only operate effectively when the wind comes from a specific direction, which reduces their efficiency in variable natural conditions. This research proposes a V-shaped galloping-based piezoelectric energy harvester (GPEH) and the triggering of its multiple modes helps broaden its effective wind direction range. A theoretical model is established using the global modal method (GMM) to characterize its bending and torsional modes and verified by finite element analysis (FEA) in terms of natural frequencies and mode shapes and further validated through wind tunnel testing. Subsequently, the output performance of the proposed V-shaped GPEH is further tested and it is demonstrated to be able to effectively harvest wind energy from multiple incident wind directions through the activation of bending and torsional modes. Moreover, both theoretical and experimental results demonstrate that higher electrical voltage and power output are achieved when galloping is triggered in the 2nd order bending mode, compared to other modes. The design and modeling of the developed V-shaped galloping-based energy harvester present an effective strategy for capturing wind flow energy in natural environments characterized by uncertain wind conditions.