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An internal-variable-based interface model for the charging process of ferroelectrets

Xu, Bai-Xiang and von Seggern, Heinz and Zhukov, Sergey and Gross, Dietmar (2014):
An internal-variable-based interface model for the charging process of ferroelectrets.
In: European Journal of Mechanics - A/Solids, Elsevier Science Publishing, pp. 97-111, 48, [Article]

Abstract

Electrically charged micro-porous foams, referred to as ferroelectrets, exhibit a very large longitudinal piezoelectric coefficient. In the present configuration the microporous material is sandwiched between two solid materials which can block the motion of charges. During the charging process of the ferroelectret electrical breakdown (Paschen breakdown) takes place in the air pores of the foam and introduce free charge pairs. These pairs are separated by the electric field induced by the applied voltage. Depending on the polarity they are relocated at the interfaces between the polymer and the electrically broken-down medium, where they are trapped quasistatically. Charging of the interfaces is key for the observed piezoelectricity of ferroelectrets. In the present article, an internal-variable-based interface model is proposed to simulate the charging and discharging of ferroelectrets. The model includes also the electrostatic force between the interface charges. For the bulk behavior, an electromechanical model based on the Maxwell stress is used. In particular, a 2D nonlinear finite element implementation of the models is elaborated, which involves a novel embedded interface element. Simulations of a sandwiched ferroelectret show that the interface model can reproduce the hysteresis behavior of the interface charge density, as it is demonstrated by the comparison with the corresponding experimental results. The model is further used to numerically study the influences of geometric, elastic and electrical parameters on the hysteresis and the piezoelectric coefficients. The models are also used to simulate a lens-shaped ferroelectret unit.

Item Type: Article
Erschienen: 2014
Creators: Xu, Bai-Xiang and von Seggern, Heinz and Zhukov, Sergey and Gross, Dietmar
Title: An internal-variable-based interface model for the charging process of ferroelectrets
Language: English
Abstract:

Electrically charged micro-porous foams, referred to as ferroelectrets, exhibit a very large longitudinal piezoelectric coefficient. In the present configuration the microporous material is sandwiched between two solid materials which can block the motion of charges. During the charging process of the ferroelectret electrical breakdown (Paschen breakdown) takes place in the air pores of the foam and introduce free charge pairs. These pairs are separated by the electric field induced by the applied voltage. Depending on the polarity they are relocated at the interfaces between the polymer and the electrically broken-down medium, where they are trapped quasistatically. Charging of the interfaces is key for the observed piezoelectricity of ferroelectrets. In the present article, an internal-variable-based interface model is proposed to simulate the charging and discharging of ferroelectrets. The model includes also the electrostatic force between the interface charges. For the bulk behavior, an electromechanical model based on the Maxwell stress is used. In particular, a 2D nonlinear finite element implementation of the models is elaborated, which involves a novel embedded interface element. Simulations of a sandwiched ferroelectret show that the interface model can reproduce the hysteresis behavior of the interface charge density, as it is demonstrated by the comparison with the corresponding experimental results. The model is further used to numerically study the influences of geometric, elastic and electrical parameters on the hysteresis and the piezoelectric coefficients. The models are also used to simulate a lens-shaped ferroelectret unit.

Journal or Publication Title: European Journal of Mechanics - A/Solids
Volume: 48
Publisher: Elsevier Science Publishing
Uncontrolled Keywords: Hysteresis, Internal variable, Piezoelectric constant
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Electronic Materials
11 Department of Materials and Earth Sciences > Material Science > Mechanics of functional Materials
Zentrale Einrichtungen
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > B - Characterisation
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > B - Characterisation > Subproject B7: Polarisation and charging in electrical fatigue ferroelectrics
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > C - Modelling
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > C - Modelling > Subproject C6: Micromechanical Simulation on Interaction of Point Defects with Domain Structure in Ferroelectrics
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Exzellenzinitiative
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres
DFG-Collaborative Research Centres (incl. Transregio)
Exzellenzinitiative > Graduate Schools > Graduate School of Computational Engineering (CE)
Exzellenzinitiative > Graduate Schools
Date Deposited: 24 Oct 2014 13:07
Additional Information:

SFB 595 Cooperation C6, B7 Frontiers in Finite-Deformation Electromechanics

Identification Number: doi:10.1016/j.euromechsol.2013.12.011
Funders: The authors would like to thank the German Research Foundation (DFG) for its financial support in the framework of the Collaborative Research Center (SFB 595) and the DFG project SE 941/17-1.
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