Free-energy density functions for nematic elastomers

Fried, Eliot; Sellers, Shaun

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https://hdl.handle.net/2142/302 Copy

Description

Title

Free-energy density functions for nematic elastomers

Author(s)

• Fried, Eliot
• Sellers, Shaun

Issue Date

2003-09

Abstract

The recently proposed neo-classical theory for nematic elastomers is a molecular-statistical generalization of classical Gaussian network theory. The resulting free-energy density predicts the phenomenon of soft elasticity—the ability of elastomers to undergo large deformations with zero force and energy cost. The theory, however, suffers from several drawbacks: (i) extreme non-uniqueness as zero applied force corresponds to infinitely many possible deformations, (ii) insufficient moduli to model observed experimental behavior, and (iii) physically, a small, but non-zero, force must be applied. Here we propose an alternative continuum model for nematic elastomers that removes these drawbacks. Motivated by the molecular-statistical theory, we identify microstructural degrees of freedom as well as two independent strain tensors (the overall macroscopic strain plus a relative strain that indicates how the deformation of the elastomeric microstructure deviates from the macroscopic deformation) and propose expressions for the free energy as a function of the three quantities. The resulting theory provides a self-consistent bridge that connects neo-classical theory to continuum microstructural theories as well as to the classical theory of anisotropic nonlinearly elastic solids.

Publisher

Department of Theoretical and Applied Mechanics (UIUC)

Series/Report Name or Number

TAM Reports 1034

ISSN

0073-5264

Type of Resource

text

Language

en

Permalink

http://hdl.handle.net/2142/302

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