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arXiv · 2607.11799

Universal scalings and switching entropy in yield-stress fluids

Rajam Elancheliyan·Jean Marc Fromental·Edouard Chauveau·Domenico Truzzolillo
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Abstract

Yield-stress fluids transition from solid-like to liquid-like behavior at a critical stress threshold, governing phenomena from industrial processing to geological flows. While predominantly investigated under steady shear, large-amplitude oscillatory tests force these materials to cyclically navigate between arrested and fluidized states. Here, we discover a hidden universal behavior where the dynamic viscoelastic moduli of yield-stress fluids collapse onto master curves, revealing that these materials rearrange almost instantaneously to maintain a constant intra-cycle stress state. We fully capture this behavior using a novel theoretical framework based on the minimization of a governing function that exhibits symmetry breaking. Our findings reveal that recoverable elastic energy, yielding abruptness, and entropy production during stress inversion are fundamentally intertwined. This connection provides a unified physical picture for the dynamic yield stress, offering a novel thermomechanical foundation to define and predict this threshold across soft matter physics and materials science.

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Rajam Elancheliyan, Jean Marc Fromental, Edouard Chauveau, Domenico Truzzolillo. 2026-07-13. Universal scalings and switching entropy in yield-stress fluids. https://arxiv.org/abs/2607.11799

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