LAUSR

The flexoelectric effect can be enhanced at the micro/nanoscale due to its size-dependency, so it is more suitable for energy harvesting than piezoelectric energy harvesters. To enhance the energy harvesting performance, this paper theoretically investigates the energy harvesting characteristics of micro circular plates with variable material properties and with consideration of the flexoelectric effect. The energy variational principle is resorted to formulate the governing equations of double-layer Kirchhoff micro circular plates, which then the analytical solutions of mechanical and electrical responses are solved. The theoretical model is validated by comparing with simulation results obtained from COMSOL Multiphysics. Furthermore, the parameter studies are addressed to discuss the influence of radial gradient index, resistance, and geometric parameters. Numerical results show that the size effect and the radial gradient distributions significantly influence the frequency response and the energy conversion efficiency. Compared with the homogeneous flexoelectric structure, the maximum power density of the proposed model is greatly improved. This research provides fundamental theoretical support and is helpful to design high-performance nanoscale energy harvesters.