Avalanche dynamics in sheared athermal particle packings occurs via localized bursts predicted by unstable linear response
Avalanche dynamics in sheared athermal particle packings occurs via localized bursts predicted by unstable linear response
复制标题
剪切非热粒子堆积中的雪崩动力学通过不稳定线性响应预测的局部爆发发生
DOI：
10.1039/d1sm01451j
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发表时间：
2022
期刊：
影响因子：
3.4
通讯作者：
Manning, M. Lisa
中科院分区：
文献类型：
--
作者：
Stanifer, Ethan;Manning, M. Lisa
在施加的剪切应变下，颗粒状和无定形材料通过颗粒重排而变形，颗粒重排可以是小的并且局部化或组织成跨越系统的雪崩。虽然准静态剪切下的雪崩的统计特性得到了很好的研究，雪崩过程中的动态没有。在剪切软球的数值模拟中，我们发现，雪崩可以分解成突发的本地化变形，我们确定使用持久的同源性方法的扩展。我们还研究了雪崩过程中不稳定系统的线性响应，表明在这种事件中，本征值动力学是非常复杂的，最不稳定的本征向量是一个很差的预测雪崩动力学。相反，我们修改现有的工具，确定本地化的激发在稳定的系统，并将它们应用到这些不稳定的系统与非正定海森，量化雪崩过程中的这种激发的演变。我们发现，在雪崩的局部化变形的爆发几乎总是发生在本地化的激发确定使用的线性光谱。这些新工具将提供一个改进的框架，用于验证和扩展中尺度弹塑性模型，这些模型通常用于解释玻璃和颗粒物质中的雪崩统计。
Under applied shear strain, granular and amorphous materials deform via particle rearrangements, which can be small and localized or organized into system-spanning avalanches. While the statistical properties of avalanches under quasi-static shear are well-studied, the dynamics during avalanches is not. In numerical simulations of sheared soft spheres, we find that avalanches can be decomposed into bursts of localized deformations, which we identify using an extension of persistent homology methods. We also study the linear response of unstable systems during an avalanche, demonstrating that eigenvalue dynamics are highly complex during such events, and that the most unstable eigenvector is a poor predictor of avalanche dynamics. Instead, we modify existing tools that identify localized excitations in stable systems, and apply them to these unstable systems with non-positive definite Hessians, quantifying the evolution of such excitations during avalanches. We find that bursts of localized deformations in the avalanche almost always occur at localized excitations identified using the linear spectrum. These new tools will provide an improved framework for validating and extending mesoscale elastoplastic models that are commonly used to explain avalanche statistics in glasses and granular matter.