Voltage-Induced Wrinkling in a Constrained Annular Dielectric Elastomer Film (original) (raw)

Two types of transitions to wrinkles in dielectric elastomers

2012

A membrane of a dielectric elastomer coated with compliant electrodes may form wrinkles as the applied voltage is ramped up. We present a combination of experiment and theory to investigate the transition to wrinkles using a clamped membrane subject to a constant force and a voltage ramp. Two types of transitions are identified. In type-I transition, the voltage–stretch curve is N-shaped, and flat and wrinkled regions coexist in separate areas of the membrane.

Dynamic pattern of wrinkles in a dielectric elastomer

Soft matter, 2017

A membrane of a dielectric elastomer may undergo electromechanical phase transition from the flat to wrinkled state, when the applied voltage reaches a critical value. The wrinkled region is observed to expand at the expense of the flat region during the phase transition. In this paper, we report on a dynamic pattern of wrinkles in a circular membrane of a dielectric elastomer. During phase transition, both the flat and wrinkled regions move interchangeably in the membrane. The radial prestretch is found to significantly affect electromechanical phase transition. For example, a membrane with a small prestretch can exhibit a dynamic pattern of wrinkles, which is essentially related to snap-through instability. However, a membrane with a large prestretch undergoes continuous phase transition, without exhibiting a dynamic pattern. An analytical model is developed to interpret these experimental phenomena. Finite element simulations are performed to predict the wrinkle morphology, espec...

Propagation of instability in dielectric elastomers

2008

When an electric voltage is applied across the thickness of a thin layer of an dielectric elastomer, the layer reduces its thickness and expands its area. This electrically induced deformation can be rapid and large, and is potentially useful as soft actuators in diverse technologies. Recent experimental and theoretical studies have shown that, when the voltage exceeds some critical value, the homogenous deformation of the layer becomes unstable, and the layer deforms into a mixture of thin and thick regions.

Electro-elastocapillary Rayleigh–plateau instability in dielectric elastomer films

We demonstrate, using both finite element simulations and a linear stability analysis, the emergence of an electro-elastocapillary Rayleigh–plateau instability in dielectric elastomer (DE) films under 2D, plane strain conditions. When subject to an electric field, the DEs exhibit a buckling instability for small elasto-capillary numbers. For larger elastocapillary numbers, the DEs instead exhibit the Rayleigh–plateau instability. The stability analysis demonstrates the critical effect of the electric field in causing the Rayleigh– plateau instability, which cannot be induced solely by surface tension in DE films. Overall, this work demonstrates the effects of geometry, boundary conditions, and multi-physical coupling on a new example of Rayleigh–plateau instability in soft solids.

Complex interplay of nonlinear processes in dielectric elastomers

2012

An elastomeric membrane can be readily stretched to many times its initial area by mechanical forces, but inducing such a large deformation by voltage is difficult. An important discovery was made about a decade ago that voltage-induced deformation can be greatly enhanced by prestretch [1, 2], which also increases the apparent electric breakdown field more than ten times [3, 4].

Mechanisms of large actuation strain in dielectric elastomers

2011

Abstract Subject to a voltage, a dielectric elastomer (DE) deforms. Voltage-induced strains of above 100% have been observed when DEs are prestretched, and for DEs of certain network structures. Understanding mechanisms of large actuation strains is an active area of research. We propose that the voltage-stretch response of DEs may be modified by prestretch, or by using polymers with “short” chains. This modification results in suppression or elimination of electromechanical instability, leading to large actuation strains.

Taut states of dielectric elastomer membranes

Actuation devices based on dielectric elastomers, typically exhibit various kinds of instability which may determine a decrease of performances and, eventually, the device failure. In this work we focus on wrinkling instabilities for polymer films subjected to an electric field. The main result is the definition of a domain of taut states in the plane of principal stretches strongly dependent on the applied voltage and on the constitutive properties of the polymer film. We discuss these features, crucial in the perspective of electroactive materials design, through simple boundary value problems for Neo-Hookean and Ogden materials.

Dielectric elastomer membranes undergoing inhomogeneous deformation

2009

Abstract Dielectric elastomers are capable of large deformation subject to an electric voltage and are promising for use as actuators, sensors, and generators. Because of large deformation, nonlinear equations of states, and diverse modes of failure, modeling the process of electromechanical transduction has been challenging.