dielectric elastomer

A combination of experiment and theory shows that dielectric elastomers exhibit complex interplay of nonlinear processes. Membranes of a dielectric elastomer are prepared in various states of prestretches by using rigid clamps and mechanical forces.

Choon Chiang Foo, Soo Jin Adrian Koh, Christoph Keplinger, Rainer Kaltseis, Siegfried Bauer, Zhigang Suo.

Performance of dissipative dielectric elastomer generators.
Journal of Applied Physics 111, 094107 (2012)

Dear Colleagues,

We would like to to draw your attention to the Symposium on **Soft Materials and Structures** to take place at the upcoming49th Meeting of the Society of Engineering Sciences(SES) at GeorgiaTech, Atlanta, GA (October 10-12, 2011). More information can be found in the meeting's website:http://ses2012.org/

Choon Chiang Foo, Shengqiang Cai, Soo Jin Adrian Koh, Siegfried Bauer, Zhigang Suo.

Model of dissipative dielectric elastomers.
Journal of Applied Physics 111, 034102 (2012).

Abstract

The dielectric constant of elastomeric dielectric material is an
essential physical parameter, whose value may affect the
electromechanical deformation of a dielectric elastomer actuator. Since
the dielectric constant is influenced by several external factors as
reported before, and no certain value has been confirmed to our
knowledge, in the present paper, on the basis of systematical comparison
of recent past literature, we conducted extensive works on the
measurement of dielectric properties of VHB films, involving five
influencing factors: prestretch (both equal and unequal biaxial),
electrical frequency, electrode material, stress relaxation time and
temperature. Experimental results directly show that the dielectric

What is the reason behind the nonlinearity in the stress-strain curve of elastomers(Molecular Level)

For a dielectric elastomer membrane we show giant voltage-triggered expansion of area by 1692%, far beyond the largest values reported in the literature.

Abstract:A hydrostatically coupled dielectric elastomer (HCDE) actuator consists of two membranes of a dielectric elastomer, clamped with rigid circular rings.Confined between the membranes is a fixed volume of a fluid, which couples the movements of the two membranes when a voltage or a force is applied.This paper presents a computational model of the actuator, assuming that the membranes are neo-Hookean, capable of large and axisymmetric deformation.The voltage-induced deformation is described by

Dielectric elastomer (DE) is a kind of electroactive polymer material,
capable of large deformation up to 380%. However, under conservative
operating conditions, DE is susceptible to instability with a small
deformation due to various modes of failure, including electrical
breakdown, electromechanical instability (EMI), loss of tension and
rupture by stretch. This paper proposes a free energy model in the
thermodynamic system of DE involving thermoelastic strain energy,
electric energy and purely thermal contribution energy to obtain the
stability conditions of all failure modes. The numerical results
indicate that the increase in temperature can markedly contribute to
improving the entropy production, the actuation stress and the critical

A dielectric elastomer is capable of giant electromechanical actuation but fails at breakdown due to instability under certain conditions with a small deformation. By applying a mechanical pre-stretch, one obtains a stabilized large actuation.

NONEQUILIBRIUM THERMODYNAMICS OF DIELECTRIC ELASTOMERS
Xuanhe Zhao, Soo Jin Adrian Koh, Zhigang Suo

In response to a stimulus, a soft material deforms, and the deformation provides a function. We call such a material a soft active material (SAM). This review focuses on one class of soft active materials: dielectric elastomers. Subject to a voltage, a membrane of a dielectric elastomer reduces thickness and expands area, possibly straining over 100%. The phenomenon is being developed as transducers for broad applications, including soft robots, adaptive optics, Braille displays, and electric generators.

Dielectric elastomer, as an important category of electroactive polymers, is known to have viscoelastic properties that strongly affect its dynamic performance and limit its application. Very few models accounting for the effects of both electrostatics and viscoelasticity exist in the literature, and even fewer are capable of making reliable predictions under general loads and constraints. Based on the principals of nonequilibrium thermodynamics, this paper develops a field theory that fully couples the large inelastic deformations and electric fields in deformable dielectrics.

Theory of dielectric elastomers capable of giant deformation of actuation
Xuanhe Zhao,Zhigang Suo
Physical Review Letters, 104,178302(2010)

I’ve just come back from aWinter School on Dielectric Elastomer Transducers, held atMonte Verità2010年1月,瑞士- 10到16。讲座s were given by various people, covering the theory of electromechanical interaction, design of devices, development of materials, and technologies of manufacturing. I was asked to give three lectures on the theory. I attach the slides of my lectures.