Instabilities in liquid crystal elastomers

TL;DR

This paper investigates various mechanical instabilities in nematic liquid crystal elastomers, analyzing how they differ from elastic solids and how parameter fluctuations influence these phenomena, with implications for material durability.

Contribution

It provides a systematic analysis of instabilities in nematic liquid crystal elastomers, including effects of nematic components and parameter fluctuations, advancing understanding of their mechanical behavior.

Findings

Identification of instability types specific to nematic elastomers

Impact of parameter fluctuations on instability behavior

Comparison between nematic and purely elastic solid instabilities

Abstract

Stability is an important and fruitful avenue of research for liquid crystal elastomers. At constant temperature, upon stretching, the homogeneous state of a nematic body becomes unstable, and alternating shear stripes develop at very low stress. Moreover, these materials can experience classical mechanical effects, such as necking, void nucleation and cavitation, and inflation instability, which are inherited from their polymeric network. We investigate the following two problems: First, how do instabilities in nematic bodies change from those found in purely elastic solids? Second, how are these phenomena modified if the material constants fluctuate? To answer these questions, we present a systematic study of instabilities occurring in nematic liquid crystal elastomers, and examine the contribution of the nematic component and of fluctuating model parameters that follow probability laws. This combined analysis may lead to more realistic estimations of subsequent mechanical damage in nematic solid materials.