Material strength consideration in the design optimization of nonlinear energy harvester

Abstract

Cantilever-based piezoelectric energy harvesting from ambient vibrations is a viable solution for powering wireless sensors and low-power electronic devices. For realization of such technology, it is imperative to design the energy harvester with higher power output and wider operating bandwidth. The main practical constraints on the design of harvester are system mass, volume, and strength of the material. In pursuit of better performance, material strength has yet been considered in designing nonlinear energy harvesters in the literature. This article focuses on the design optimization of nonlinear energy harvester with magnetic oscillator within the limits of allowable strain on piezoelectric material. Parametric study is carried out to find the optimal configuration of nonlinear energy harvester. Experiments show that compared to the linear configuration, the optimized nonlinear energy harvester achieves higher power output and wider bandwidth with maximum strain on piezoelectric material below the allowable limit.

Nonlinear analysis and power improvement of broadband low-frequency piezomagnetoelastic energy harvesters

“…In this case, it is assumed that the magnetic dipoles' directions and the transverse deflection of the system are always vertically aligned. It was demonstrated by Upadrasta et al [45] that this model is accurate only when the spacing distance between the two magnets is sufficiently large. They showed that the dipole model gives erroneous predictions for the magnetic force when the spacing distance between the two magnets is smaller than 6.5 mm.…”

“…Consequently, the expression of the magnetic force depends on the number of considered mesh elements and hence a higher number of mesh elements is needed to have an accurate representation which can significantly increase the computational time. More details about this methodology can be found in [45]. Upadrasta et al [45] reported that a discretization error in the order of 0.001 N is obtained when considering a mesh resolution of 25 elements in the radial direction and 25 elements in the circumferential direction.…”

“…More details about this methodology can be found in [45]. Upadrasta et al [45] reported that a discretization error in the order of 0.001 N is obtained when considering a mesh resolution of 25 elements in the radial direction and 25 elements in the circumferential direction. They also showed that this formulation gives a good agreement with finite element method (FEM) when using COMSOL Multiphysics.…”

“…As a strategy to model the magnetic force, a charge model has been used by some researchers to determine a closed-form expression of the magnetic force [43][44][45]. This method is named charge dipole because it assumes a charge-charge interaction.…”

Broadband energy harvesting using nonlinear techniques

“…Shafer et al (2012) explored the limiting conditions for the utilization of a harvester beam from the ultimate strength considerations of the constituent materials. Upadrashta et al (2014) examined the material strength considerations and suggested that a limiting strain of 1000 με for the MFC transducer would restrict it within the linear range. Though these studies have provided useful guidelines, it is unlikely that the field conditions would be uniform and any harvester designed based on such conditions would lead to a very conservative design.…”