Design, analysis, and characterization of single crystal energy harvesters for rotorcraftwireless sensor applications

Vibrational energy harvesting devices are a possible solution to provide adequate power for structural health monitoring by taking ambient vibrations and converting them into usable electric power. This work aims to quantify critical single crystal energy harvester design parameters by investigating lead magnesium niobate-lead titanate (PMN-PT) single crystal devices in long-duration, high-temperature, and high acceleration environments typical of rotorcraft applications, expanding the environmental parameters from current literature, and comparing them to conventional lead zirconite titanate (PZT) ceramics. The harvesters proved to be a reliable source of power generation and are practical for harvesting usage. The work also provides new data by expanding upon current test data sets by including device damping and scalability studies and by developing and testing a compact energy harvester more representative of true flight hardware. A laboratory test article produced 25 VRMS at 1.0 g base acceleration at room temperature and was stable for 120 h of continuous use. Its performance exhibited strong temperature dependence, which was lessened by using different material compositions. The output power of a prototype, 40-g compact harvester surpassed that of PZT devices and was sufficient for low-power sensors. At 1.0 g and room temperature, the single crystal harvester produced approximately three times the power of a PZT device. A scalability study was conducted to compare size and mass of a prototype compact device for use at a range of frequencies of interest, which showed the harvester is easily scaled with minimal design changes.