TY - JOUR

T1 - Numerical model for the characterization of Maxwell-Wagner relaxation in piezoelectric and flexoelectric composite material

AU - Nguyen, B. H.

AU - Zhuang, Xiaoying

AU - Rabczuk, Timon

N1 - Funding Information: The first and second authors owe the gratitude to the sponsorship from Sofja Kovalevskaja Programme of Alexander von Humboldt Foundation. The second author thankfully acknowledges the funding State Key Laboratory of Structural Analysis for Industrial Equipment (GZ1607) and National Science Foundation of China (11772234). We also thank Dr. Nanthakumar Srivilliputtur Subbiah for fruitful discussion. Comments and suggestions from the Reviewers are greatly appreciated.

PY - 2018/10/1

Y1 - 2018/10/1

N2 - Bi-layer structures can be engineered to investigate the interfacial polarization (Maxwell-Wagner polarization) of heterogeneous dielectric material, which shows the frequency-dependent property of the effective dielectric permittivity. However, in piezoelectric or flexoelectric heterostructures, behaviors of the effective piezoelectric or flexoelectric coefficients are remained unclear. Therefore, in this work, we present a numerical model of the Maxwell-Wagner polarization effect in a bi-layer structure made of piezoelectric or flexoelectric material. In this model, the conductivity, which qualitatively represents the free charge in a real dielectric material, is introduced to the complex dielectric permittivity. Several numerical examples are performed to validate the model and investigate the frequency dependence of the effective dielectric permittivity, piezoelectric and flexoelectric coefficients as well as the giant enhancement of dielectric constants. It is found that the static (at low frequency) and the instantaneous (at high frequency) effective coefficients are governed by those of the thin and thick layer, respectively. Moreover, both conductivity and volume ratio play essential roles in the enhancement of the dielectric constant that is underpinned by the Maxwell-Wagner effect.

AB - Bi-layer structures can be engineered to investigate the interfacial polarization (Maxwell-Wagner polarization) of heterogeneous dielectric material, which shows the frequency-dependent property of the effective dielectric permittivity. However, in piezoelectric or flexoelectric heterostructures, behaviors of the effective piezoelectric or flexoelectric coefficients are remained unclear. Therefore, in this work, we present a numerical model of the Maxwell-Wagner polarization effect in a bi-layer structure made of piezoelectric or flexoelectric material. In this model, the conductivity, which qualitatively represents the free charge in a real dielectric material, is introduced to the complex dielectric permittivity. Several numerical examples are performed to validate the model and investigate the frequency dependence of the effective dielectric permittivity, piezoelectric and flexoelectric coefficients as well as the giant enhancement of dielectric constants. It is found that the static (at low frequency) and the instantaneous (at high frequency) effective coefficients are governed by those of the thin and thick layer, respectively. Moreover, both conductivity and volume ratio play essential roles in the enhancement of the dielectric constant that is underpinned by the Maxwell-Wagner effect.

KW - Colossal dielectric constant

KW - Flexoelectric

KW - Maxwell-Wagner polarization

KW - Piezoelectric

UR - http://www.scopus.com/inward/record.url?scp=85049747715&partnerID=8YFLogxK

U2 - 10.1016/j.compstruc.2018.05.006

DO - 10.1016/j.compstruc.2018.05.006

M3 - Article

AN - SCOPUS:85049747715

VL - 208

SP - 75

EP - 91

JO - Computers and Structures

JF - Computers and Structures

SN - 0045-7949

ER -