A visco-electric device for vibration energy harvesting on rotorcraft

A vibration energy harvester concept features a damped mechanical oscillator tuned to a specified excitation frequency of the vibrating structure on which it is installed. Vibration energy absorbed through the base of the harvester is dissipated as thermal energy by a viscoelastic material subject to harmonic strain at its natural frequency. Conduction of the dissipated heat to a thermal conductor results in a temperature increase of the conductor. Heat flow from the conductor element to an ambient-temperature heat sink is used to generate electrical power by means of a thermoelectric generator placed between the heated and ambient-temperature surfaces. A realization of the visco-electric harvester design is proposed, and an engineering model is developed to describe its behavior. The thermal energy output of the elastomer and steady-state temperature of the conductor element are calculated for different sets of physical properties and used to predict the electrical energy output of the device. A nominal steady-state electrical energy output of 3 mW at 4.1 VDC is predicted for a notional device.