Dynamic performance of piezoelectric energy harvesters with a multifunctional nanocomposite substrate

Abstract

In this paper, a bridge-type piezoelectric energy harvester (PEH) made of an advanced porous nanocomposite substrate activated by two piezoceramic layers is proposed. The advanced passive layer is made of a lightweight polymeric foam which is mechanically enhanced with carbon nanotubes (CNTs). Different functionally graded (FG) patterns are presumed for the distributions of voids and CNTs to enhance the electromechanical efficiency of the proposed energy harvester. Moreover, the prevalent problem of nanofiller dispersion, i.e., agglomeration formation, has been involved by employing a modified form of Eshelby-Mori-Tanaka (EMT)'s procedure. To provide highly accurate results, a higher order shear deformation theory (HSDT) of plates is utilized for the derivation of the coupled electromechanical governing equation of the proposed PEH. This dynamic equation is then treated by establishing a mesh-free method which uses moving least squares (MLSs) interpolation functions. Finally, the influences of voids, CNT and layers’ thicknesses are characterized on the electromechanical performances of the suggested PEH. The results indicate that the suggested PEH induces 3 v to 6.5 v when it deflects in the range of 50 µm to 140 µm. Moreover, the distribution of CNTs has a higher impact on the electromechanical performances than the volume fraction of CNTs. Furthermore, the results revealed that embedding pores leads to higher deflection/voltage peaks and higher frequencies of oscillations.