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Discrete rearranging disordered patterns, part II: 2D plasticity, elasticity and flow of a foam

Philippe Marmottant·Christophe Raufaste·François Graner
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Abstract

The plastic flow of a foam results from bubble rearrangements. We study their occurrence in experiments where a foam is forced to flow in 2D: around an obstacle; through a narrow hole; or sheared between rotating disks. We describe their orientation and frequency using a topological matrix defined in the companion paper (Graner et al., preprint), which links them with continuous plasticity at large scale. We then suggest a phenomenological equation to predict the plastic strain rate: its orientation is determined from the foam's local elastic strain; and its rate is determined from the foam's local elongation rate. We obtain a good agreement with statistical measurements. This enables us to describe the foam as a continuous medium with fluid, elastic and plastic properties. We derive its constitutive equation, then test several of its terms and predictions.

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Philippe Marmottant, Christophe Raufaste, François Graner. 2008-01-08. Discrete rearranging disordered patterns, part II: 2D plasticity, elasticity and flow of a foam. https://arxiv.org/abs/cond-mat/0609188

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