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arXiv · 1108.3315

Strain-stiffening in random packings of entangled granular chains

Eric Brown·Alice Nasto·Athanasios G. Athanassiadis·Heinrich M. Jaeger
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Abstract

Random packings of granular chains are presented as a model polymer system to investigate the contribution of entanglements to strain-stiffening in the absence of Brownian motion. The chain packings are sheared in triaxial compression experiments. For short chain lengths, these packings yield when the shear stress exceeds a the scale of the confining pressure, similar to packings of spherical particles. In contrast, packings of chains which are long enough to form loops exhibit strain-stiffening, in which the effective stiffness of the material increases with strain, similar to many polymer materials. The latter packings can sustain stresses orders-of-magnitude greater than the confining pressure, and do not yield until the chain links break. X-ray tomography measurements reveal that the strain-stiffening packings contain system-spanning clusters of entangled chains.

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Eric Brown, Alice Nasto, Athanasios G. Athanassiadis, Heinrich M. Jaeger. 2011-08-16. Strain-stiffening in random packings of entangled granular chains. https://doi.org/10.1103/physrevlett.108.108302

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