论文标题
剪切堵塞的密集悬浮液中两个不同的应力放松状态的起源
Origin of two distinct stress relaxation regimes in shear jammed dense suspensions
论文作者
论文摘要
许多致密的颗粒悬浮液显示应力引起的从液体状状态转变为固体样剪切状态（SJ）状态。然而，导致散装的这种醒目，可逆的过渡的潜在粒子尺度动力学仍然未知。在这里，我们研究了由阶跃应变扰动下通过良好的密度悬浮液形成的SJ状态的瞬时应力松弛行为。我们观察到一个强烈的非指数放松，对于足够高的峰值压力值，在短时间内会形成急剧的不连续性下降。高分辨率边界成像和正常应力测量结果证实，这种应力不连续性源自局部塑料事件，而跨越扩张的系统控制较慢的松弛过程。我们还发现瞬态弛豫的性质与从Wyart-Cates模型获得的稳态剪切相图之间存在着有趣的相关性。
Many dense particulate suspensions show a stress induced transformation from a liquid-like state to a solid-like shear jammed (SJ) state. However, the underlying particle-scale dynamics leading to such striking, reversible transition of the bulk remains unknown. Here, we study transient stress relaxation behaviour of SJ states formed by a well-characterized dense suspension under a step strain perturbation. We observe a strongly non-exponential relaxation that develops a sharp discontinuous stress drop at short time for high enough peak-stress values. High resolution boundary imaging and normal stress measurements confirm that such stress discontinuity originates from the localized plastic events, whereas, system spanning dilation controls the slower relaxation process. We also find an intriguing correlation between the nature of transient relaxation and the steady state shear jamming phase diagram obtained from the Wyart-Cates Model.
