The role of electrostriction on the stability of dielectric elastomer actuators

TL;DR

This paper investigates how electrostriction influences the stability of dielectric elastomer actuators, revealing its role in instabilities and band localization, which are critical for preventing electric breakdown in soft materials.

Contribution

It applies nonlinear electroelasticity theory and bifurcation analysis to elucidate electrostriction's impact on instability phenomena in dielectric elastomers.

Findings

Electrostriction enhances diffuse-mode instability.

Electrostriction is crucial for understanding band-localization.

Comparison of buckling stresses highlights stability differences.

Abstract

In the field of soft dielectric elastomers, the notion electrostriction indicates the dependency of the permittivity on strain. The present paper is aimed at investigating the effects of electrostriction onto the stability behaviour of homogeneous electrically activated dielectric elastomer actuators. In particular, three objectives are pursued and achieved: i) the description of the phenomenon within the general nonlinear theory of electroelasticity; ii) the application of the recently proposed theory of bifurcation for electroelastic bodies in order to determine its role on the onset of electromechanical and diffuse-mode instabilities in prestressed or prestretched dielectric layers; iii) the analysis of band-localization instability in homogeneous dielectric elastomers. Results for a typical soft acrylic elastomer show that electrostriction is responsible for an enhancement towards diffuse-mode instability, while it represents a crucial property - necessarily to be taken into account - in order to provide a solution to the problem of electromechanical band-localization, that can be interpreted as a possible reason of electric breakdown. A comparison between the buckling stresses of a mechanical compressed slab and the electrically activated counterpart concludes the paper.