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Modeling Dense Granular Flow: A Nonequilibrium Thermodynamics Approach and Implications of Grain Fragmentation, Acoustic Effects and Interparticle Friction on Dynamic Friction.

机译:密实颗粒流建模:一种非平衡热力学方法,涉及颗粒破碎,声学效应和颗粒间摩擦对动态摩擦的影响。

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摘要

Granular flow rheology has broad implications on earth science and industrial processing of raw materials. This dissertation is an overview of our effort to understand dense granular flow and the influence of microscopic, grain-scale processes on dynamic friction from basic principles of nonequilibrium thermodynamics. First, I will provide a short introduction to the Shear-Transformation-Zone (STZ) theory of plastic deformation and the underlying theoretical framework of nonequilibrium thermodynamics, and use the Haxton-Liu hard-sphere simulations as a testing ground for the theory. Next, I will briefly discuss grain fragmentation and examine its implication on shear weakening and shear localization; in so doing, we account for the formation and persistence of shear bands of fragmented particles. Finally, I propose a way to incorporate acoustic effects, particle angularity, and interparticle friction into the STZ model. We show good agreement with laboratory experiments on angular sand particles that indicate shear-induced acoustic compaction at intermediate strain rates. We show in addition that friction between particles is essential in producing stick-slip instabilities, which can be controlled by the confining pressure and external vibrations.
机译:颗粒流变学对地球科学和原材料的工业加工具有广泛的意义。本文从非平衡热力学的基本原理出发,概述了我们为了解致密颗粒流动以及微观,晶粒度过程对动摩擦的影响所做的努力。首先,我将简要介绍塑性变形的剪切变形区(STZ)理论和非平衡热力学的基本理论框架,并使用Haxton-Liu硬球模拟作为该理论的试验基础。接下来,我将简要讨论晶粒破碎,并研究其对剪切弱化和剪切局部化的影响。在此过程中,我们考虑了碎裂颗粒剪切带的形成和持久性。最后,我提出了一种将声音效果,粒子角度和粒子间摩擦纳入STZ模型的方法。我们在有角度的沙粒上显示出与实验室实验的良好一致性,这些实验表明中等应变速率下的剪切诱导声压实。我们还表明,颗粒之间的摩擦对于产生粘滑不稳定性至关重要,粘滑不稳定性可以通过限制压力和外部振动来控制。

著录项

  • 作者

    Lieou, Charles Ka Cheong.;

  • 作者单位

    University of California, Santa Barbara.;

  • 授予单位 University of California, Santa Barbara.;
  • 学科 Geophysics.;Materials science.
  • 学位 Ph.D.
  • 年度 2015
  • 页码 162 p.
  • 总页数 162
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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