Abstract
This study employs the Element-Free Galerkin method (EFG) to characterize flexoelectricity in a composite material. The presence of the strain gradient term in the Partial Differential Equations (PDEs) requires C 1 continuity to describe the electromechanical coupling. The use of quartic weight functions in the developed model fulfills this prerequisite. We report the generation of electric polarization in a non-piezoelectric composite material through the inclusion-induced strain gradient field. The level set technique associated with the model supervises the weak discontinuity between the inclusion and matrix. The increased area ratio between the inclusion and matrix is found to improve the conversion of mechanical energy to electrical energy. The electromechanical coupling is enhanced when using softer materials for the embedding inclusions.
Highlights
An energy harvester utilizing the electromechanical coupling effect has been applied in various applications, ranging from sensors [1,2,3] to biomedical devices [4,5] at both micro- and nano-scales [6,7,8].The well-known electromechanical coupling effect, piezoelectricity, generates the electrical polarization under mechanical deformation only in the non-centrosymmetric material
The proposed model demonstrates the possibilities of inducing electromechanical coupling in a nano-composite material without the presence of the piezoelectric effect
The C1 continuity due to the strain gradient term is fulfilled by choosing the special weight function in the Element-Free Galerkin method (EFG)
Summary
An energy harvester utilizing the electromechanical coupling effect has been applied in various applications, ranging from sensors [1,2,3] to biomedical devices [4,5] at both micro- and nano-scales [6,7,8]. The well-known electromechanical coupling effect, piezoelectricity, generates the electrical polarization under mechanical deformation only in the non-centrosymmetric material Flexoelectricity is another type of electromechanical coupling, which describes the coupling between the electrical potential and strain gradient. Experimental studies [9,10] observed an unexpected giant flexoelectric effect in barium strontium titanate, which suggested that at the micro-/nano-scale, the flexoelectric effect outperforms the piezoelectric effect These superior properties of flexoelectricity at a small scale have drawn extensive research attention towards the fundamental investigation of this electromechanical coupling from the molecular scale to the continuum scale. The Extended Finite Element Method (XFEM) has been used for the level set technique to describe the weak discontinuity between the inclusion and matrix composite [42,43,44].
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