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Studying Large Amplitude Oscillatory Shear Response of Soft Materials
Published on: April 25, 2019
Semisoft elastic response of nematic elastomers to complex deformations
J S Biggins1, E M Terentjev, M Warner
1Cavendish Laboratory, Madingley Road, Cambridge, CB3 0HE, United Kingdom.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|November 13, 2008
Summary
This study on semisoft elastomers reveals kinks in stress-strain curves and shear modulus zeros during director rotation. These findings offer a robust method for testing theories of elastomer behavior.
Area of Science:
- Materials Science
- Polymer Physics
- Continuum Mechanics
Background:
- Semisoft elastomers exhibit unique mechanical properties influenced by director orientation.
- Large stretches can induce director rotation, affecting material response.
- Understanding these phenomena is crucial for predicting elastomer behavior under complex loading conditions.
Purpose of the Study:
- To investigate the relationship between director rotation and mechanical responses in semisoft elastomers.
- To identify characteristic features in stress-strain curves and shear modulus during director rotation.
- To propose a theoretical framework for testing semisoft elastomer models.
Main Methods:
- Theoretical analysis of a relaxed semisoft elastomer subjected to large stretch and shear.
- Derivation of analytical forms for shear modulus (C5) as a function of strain.
- Comparison of theoretical predictions with existing stress-strain data.
Main Results:
- Predicted kinks in the stress-large strain curve (stress-strain plateau) during director rotation.
- Predicted zeros in the x-z shear modulus (C5) at the onset and end of director rotation.
- Analytical forms for C5-strain curves derived for a compositional fluctuations model.
Conclusions:
- The observed kinks and modulus zeros provide a strong basis for testing theories of semisoft elastomers.
- The compositional fluctuations model yields a general form for quadratic free energy.
- Further development of models incorporating additional directional dependencies is possible.
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