Voltage-controlled radial wrinkles of a trumpet-like dielectric elastomer structure

Guoyong Mao,Junjie Liu,Shaoxing Qu,Yimou Fu,Lei Wu

doi:10.1063/1.5021028

Abstract

Wrinkle is usually considered as one failure mode of membrane structure. However, it can also be harnessed in developing smart devices such as dry adhesion tape, diffraction grating, smart window, etc. In this paper, we present a method to generate voltage-controlled radial wrinkles, which are fast response and reversible, in a stretched circular dielectric elastomer (DE) membrane with boundary fixed. In the experiment, we bond a circular plate on the center of the circular membrane and then pull the DE membrane perpendicular to itself via the plate. The stretched DE membrane is a trumpet-like structure. When the stretched DE membrane is subjected to a certain voltage, wrinkles nucleate from the center of the DE membrane and propagate to the boundary as the voltage increases. We adopt a theoretical framework to analyze the nucleation of the wrinkles. A simple wavelength expression is achieved, which is only related to the geometry and the stretch of the DE membrane. Results show that the theory agrees well with the experiment. This work may help the future design of DE actuators in avoiding mechanical instability and provide a new method to generate controllable radial DE wrinkles.

Highlights

Wrinkle is one typical structure instability in membrane structure, it shows the potential in applications including modulus measurement, dry adhesion, smart window, stretchable electronics and so on.[1,2,3,4] Compressive stress is the key factor to induce wrinkle, which can result from various stimuli such as mechanical load, heat, light, electricity, swelling and so on.[5,6,7,8,9] most of the traditional stimuli are slow to activate the wrinkles and some may induce irreversible deformation
Liu et al analyze the relationship of critical voltage of mechanical wrinkling and electrical breakdown with a prestretched membrane clamped by a square-ring frame.[11]
They experimentally analyze the morphology of dielectric elastomer (DE) wrinkle, i.e., wavelength and amplitude, and find out both the wavelength and amplitude of wrinkles decrease with aspect ratios of the DE membrane

Summary

Introduction

Wrinkle is one typical structure instability in membrane structure, it shows the potential in applications including modulus measurement, dry adhesion, smart window, stretchable electronics and so on.[1,2,3,4] Compressive stress is the key factor to induce wrinkle, which can result from various stimuli such as mechanical load, heat, light, electricity, swelling and so on.[5,6,7,8,9] most of the traditional stimuli are slow to activate the wrinkles and some may induce irreversible deformation. When we apply a voltage φ to the DE membrane, wrinkles will nucleate around the inner boundary of the specimen (trumpet-like DE structure) as Fig. 2 shows. With the increase of the voltage, the radial wrinkles nucleate and propagate from the center to the outer boundary of the specimen.

Results

Conclusion