Normal stresses, contraction, and stiffening in sheared elastic networks

Journal article (2018)

Authors

K. Baumgarten Engineering Thermodynamics - Mechanical, Maritime and Materials Engineering
B.P. Tighe Engineering Thermodynamics - Mechanical, Maritime and Materials Engineering
Research Group
Engineering Thermodynamics (Mechanical, Maritime and Materials Engineering) (TU Delft)
Copyright: © 2018 K. Baumgarten, B.P. Tighe
DOI: https://doi.org/10.1103/PhysRevLett.120.148004
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Published Date

2018

Language

English

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Faculty

Mechanical, Maritime and Materials Engineering

Department

Process and Energy

Research Group

Engineering Thermodynamics

Abstract

When elastic solids are sheared, a nonlinear effect named after Poynting gives rise to normal stresses or changes in volume. We provide a novel relation between the Poynting effect and the microscopic Grüneisen parameter, which quantifies how stretching shifts vibrational modes. By applying this relation to random spring networks, a minimal model for, e.g., biopolymer gels and solid foams, we find that networks contract or develop tension because they vibrate faster when stretched. The amplitude of the Poynting effect is sensitive to the network's linear elastic moduli, which can be tuned via its preparation protocol and connectivity. Finally, we show that the Poynting effect can be used to predict the finite strain scale where the material stiffens under shear.