Parametric Analysis of a Piezoelectric Flexoelectric Energy Harvesting Nanosystem

Flexoelectricity is defined as an electromechanical coupling between polarization and strain gradient which makes its effect largely dominant at the nanoscale. Using a decent electromechanical modelling of a piezoelectric flexoelectric nanobeam made of BaTiO3, we simulate the dynamic behaviour of the device as energy harvester when it is subjected to a base harmonic excitation representing mechanical vibrations from the environment. Considering the aspect ratio of the beam, the Timoshenko beam theory was used to model the energy harvesting system. A bidirectional aspect of the electric filed is considered and a nonlinear variation of the electric potential is adopted providing a more accurate modelling. Using the Hamilton’s principle and then the Galerkin procedure, the reduced-order model is established and solved for respectively the deflection of the nanobeam, the electric potential and the generated electrical voltage across a resistance load. The scale and aspect ratio are varied in order to analyse their effect on the dynamic response of the nanobeam and the generated electrical power. The results showed higher power density generation when the aspect ratio of the nanobeam is increased. The scale effect due to the nonlocal aspect of the formulation reduces the expected performance of the device.