A model for capturing the rate-dependent mechanical behaviour of liquid crystal elastomers

Afshin Anssari-Benam, Giuseppe Saccomandi

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Abstract

A modelling framework is adopted and adapted here to model the rate-dependent deformation behaviour of liquid crystal elastomers (LCEs). On using an isotropic hyperelastic strain energy function of binomial form, previously employed for capturing the (quasi-static) deformation of polydomain LCEs, an extension is presented for application to the rate-dependent behaviour of LCEs by incorporating the deformation rate into the model parameters. That is, the model parameters of the core hyperelastic strain energy function are considered to evolve with, i.e., be a function of, the deformation rate. A specific measure of deformation rate ɛ is utilised, and a particular functional dependency of the hyperelastic model parameters on ɛ, of a skewed exponential form, is devised and presented. The ensuing rate-dependent model is then applied to a range of extant experimental datasets, encompassing various LCE specimens and across different deformation rates, under uniaxial loading and including both tension and compression deformations. The model is shown to capture and predict the data favourably. Given the simplic of devising and implementing the presented modelling framework, the flexibility it provides for incorporating different choices of strain energy function as well as the functional form(s) of the dependency of the model parameters on the deformation rate, and the accuracy of the modelling results, the application of this modelling approach to capturing the rate-dependent deformation behaviour of LCEs is hereby presented.
Original languageEnglish
Article number105108
Number of pages13
JournalMechanics of Materials
Volume198
Early online date12 Aug 2024
DOIs
Publication statusEarly online - 12 Aug 2024

Keywords

  • Liquid crystal elastomers
  • Rate-dependent behaviour
  • Constitutive modelling
  • Pseudo-hyperelastic function
  • Soft elastic

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