Auxetic piezoelectric energy harvesters for increased electric power output

Abstract

This letter presents a piezoelectric bimorph with auxetic (negative Poisson’s ratio) behaviors for increased power output in vibration energy harvesting. The piezoelectric bimorph comprises a 2D auxetic substrate sandwiched between two piezoelectric layers. The auxetic substrate is capable of introducing auxetic behaviors and thus increasing the transverse stress in the piezoelectric layers when the bimorph is subjected to a longitudinal stretching load. As a result, both 31- and 32-modes are simultaneously exploited to generate electric power, leading to an increased power output. The increasing power output principle was theoretically analyzed and verified by finite element (FE) modelling. The FE modelling results showed that the auxetic substrate can increase the transverse stress of a bimorph by 16.7 times. The average power generated by the auxetic bimorph is 2.76 times of that generated by a conventional bimorph.

Review of nonlinear vibration energy harvesting: Duffing, bistability, parametric, stochastic and others

“…Auxetics have already been demonstrated to help enhance the power efficiency for harnessing direct contact kinetic energy along with triboelectric (Zhang et al, 2017) and piezoelectric (Li et al, 2017) generators. However, its effectiveness to enhance more dynamic kinetic energy and its vibrational frequency behaviour are yet to be fully investigated.…”

Finite Element Analysis of Tunable Composite Tubes Reinforced with Auxetic Structures

“…However, when considering the tube, the effective Poisson’s ratio of stretched (compressed) tube is calculated on the basis of the change of the length of its circumference, which could be expressed simply by its diameter or radius. Hence, the effective Poisson’s ratio of the axially stretched tube is given by the following [ 39 ]: where —average circumferential strains and , and . Given the fact that the composite material properties are not homogeneous in the cross-sectional area, one should expect that the deformed cross-section could diverge from its initial circular shape.…”

“…Alderson et al [ 38 ] discussed piezomorphic materials i.e., materials that change smoothly their shape in response to mechanical stress. Piezoelectric bimorph composite with auxetic phase used for increased power output in vibration energy harvesting [ 39 ]. The influence of magnetic field and the behaviour of magneto-auxetic systems have been investigated by Grima et al [ 40 ] and Dudek et al [ 41 , 42 ].…”

Enhancement of piezoelectric vibration energy harvesting with auxetic boosters

“…A piezoelectric bimorph with auxetic structure has been introduced, which could improve the harvested power up to 2.76 times. 37 A triboelectric self-powered sensor with auxetic foam has been fabricated, and its performance has been tested. 38 A strain vibration energy harvester with an auxetic structure was proposed for a strip under tension.…”