Energy harvesting from a nanopiezoelectric/piezomagnetic sandwich beam with porous properties

Abstract

Piezoelectric/piezomagnetic energy harvester has attracted great interest, which can convert magnetic energy into electric power. However, the challenges are how to provide lasting electric energy to the nanoscale components and avoid the inherent brittleness of the piezoelectric and piezomagnetic materials. Therefore, a nanoporous piezoelectric/piezomagnetic beam with a storage circuit is proposed to be an energy harvester in this paper. The nanoporous beam is treated as a sandwich composite beam with the piezoelectric/piezomagentic core bulks and the surface or interface layers. Based on the surface effect theory and the Boit’s porous elasticity, the governing equations and the analytical solutions of the nanoporous piezoelectric/piezomagnetic energy harvester with the flexural mode are obtained. The numerical calculation points out that the resonant frequency, output power density and the output voltage depend on the surface materials parameters, porosity properties, solid-fluid coupling effects, the geometrical dimensions, as well as the piezoelectric/piezomagnetic materials composition of the structure. The results reveal that the resonant frequency interval can be controlled and the output electric power can be improved by adjusting the materials and geometrical parameters.