Long-Lived Neighbors Determine the Rheological Response of Glasses
Long-Lived Neighbors Determine the Rheological Response of Glasses
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DOI：
10.1103/physrevlett.118.018002
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发表时间：
2017-01-06
影响因子：
8.6
通讯作者：
Zaccone, A.
中科院分区：
文献类型：
--
作者：
Laurati, M.;Masshoff, P.;Zaccone, A.
玻璃表现出类似液体的结构，但类似固体的流变学响应，塑性变形仅发生在屈服之后。因此，从微观结构预测流变行为是困难的，但对于材料科学来说很重要。在这里，我们考虑胶体悬浮液，并建议补充静态结构信息与当地的动态，即，重新安排和打破笼子的邻居。这通过均方非仿射位移和长时间保持最近邻的粒子的数量来量化，即，长寿的邻居，分别。这两个量都遵循剪切下使用共聚焦显微镜，是基础上计算的仿射和非仿射贡献的弹性应力，这是补充的粘弹性应力，给出总应力。在启动剪切，该模型预测三个瞬态制度，从仿射，非仿射和粘弹性的贡献的相互作用的结果。我们的预测与流变数据及其对体积分数和剪切速率的依赖性定量一致。
Glasses exhibit a liquidlike structure but a solidlike rheological response with plastic deformations only occurring beyond yielding. Thus, predicting the rheological behavior from the microscopic structure is difficult, but important for materials science. Here, we consider colloidal suspensions and propose to supplement the static structural information with the local dynamics, namely, the rearrangement and breaking of the cage of neighbors. This is quantified by the mean squared nonaffine displacement and the number of particles that remain nearest neighbors for a long time, i.e., long-lived neighbors, respectively. Both quantities are followed under shear using confocal microscopy and are the basis to calculate the affine and nonaffine contributions to the elastic stress, which is complemented by the viscoelastic stress to give the total stress. During start-up of shear, the model predicts three transient regimes that result from the interplay of affine, nonaffine, and viscoelastic contributions. Our prediction quantitatively agrees with rheological data and their dependencies on volume fraction and shear rate.