Catastrophic thinning of dielectric elastomers

TL;DR

This paper offers an analytical understanding of the creasing and pull-in instabilities in thin dielectric elastomers, providing formulas to predict voltage thresholds and shapes, aiding the development of reliable soft actuators.

Contribution

It introduces a simple, fully analytical model for predicting and understanding catastrophic instabilities in dielectric elastomers, avoiding complex simulations.

Findings

Derived a formula for voltage thresholds of instabilities

Modelled the shape of creasing and pull-in patterns

Confirmed predictions align with experimental results

Abstract

We provide a clear energetic insight into the catastrophic nature of the so-called creasing and pull-in instabilities in soft electro-active elastomers. These phenomena are ubiquitous for thin electro-elastic plates and are a major obstacle to the development of giant actuators; yet they are not completely understood nor modelled accurately. Here, in complete agreement with experiments, we give a simple formula to predict the voltage thresholds for these instability patterns and model their shape, and show that equilibrium is impossible beyond their onset. Our analysis is fully analytical, does not require finite element simulations, and can be extended to include pre-stretch and to encompass any material behaviour.