Piezoelectric micro power harvester using flow-induced vibration for intrastructure health monitoring applications

Abstract

A piezoelectric micro power harvester from flow-induced vibration is developed to investigate change to the geometrical properties of engineering structures. The presented piezoelectric micro power harvester generates electrical energy resulting from wind flow around the harvester, while conventional ones produce electrical energy in response to parasitic vibration. The micro power harvester is composed of four silicon cantilevers coated with a piezoelectric film, each of which has a length of 2,000 μm, a width of 200 μm, and a thickness of 3.5 μm; the cantilevers are slightly bent (about 83.2 μm in a upward direction) using residual stress of the piezoelectric film to effectively convert flow-induced vibration into electrical energy. When the bent micro-cantilevers are exposed to wind, the structures undergo flow-induced vibration which results in electrical power based on piezoelectricity. Our micro power harvester generates enough electrical power, proportional to flow velocity, for structural health monitoring systems, for example an average maximum power density of 441.8 μW/cm2 at a flow velocity of 12.4 m/s with a single cantilever.