Effect of auxetic structures parameters variation on PVDF-based piezoelectric energy harvesters

Abstract

This work deals with enhancing piezoelectric energy harvesting by incorporating different auxetic structures and varying geometrical parameters. A bimorph consisting of polyvinylidene fluoride as a piezoelectric layer and brass auxetic substrate (re-entrant, s-shape, and elliptical holes) are considered for analysis. A finite element method-based simulation is performed to find the best auxetic systems that provide higher power output. The environmental vibration is taken for energy harvesting

thus, the first resonance frequency is below 100 Hz. The maximum power of ∼0.52, ∼0.67, and ∼0.79 mW is estimated for piezoelectric energy harvesters (PEH's) re-entrant, s-shape, and elliptical holes. The auxetic re-entrant, s-shape, and elliptical substrate-based PEHs show 200%, 300%, and 333% more power than the solid substrate (conventional design). However, the elliptical-based auxetic structure obtains a maximum power density of 0.004 66 mW/mm3. The stresses in all structures are within the permissible limit

hence, any design can be used for practical applications. All three auxetics have comparable geometrical dimensions and the same material is used

thus, auxetic behavior is independent of the material employed and depends on the structure's shape. The estimated power is higher than that reported in the literature. © 2022 Author(s).