A tale of two viscosities
A tale of two viscosities
复制标题
两种粘度的故事
DOI：
10.1016/j.jsg.2009.04.010
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发表时间：
2009
影响因子：
3.1
通讯作者：
C. Wilson
中科院分区：
文献类型：
--
作者：
M. Jessell;P. Bons;A. Griera;L. Evans;C. Wilson
我们描述了一系列针对两相线性和非线性粘性材料的 12 个大应变、二维简单剪切数值实验。两相的模态百分比、它们的相对粘度以及粘度对应力依赖性的应力指数是系统变化的，使我们能够观察这些参数对系统流动行为的影响。所有实验都表现出局域化，但局域化的程度和类型差异很大，并且参数范围允许经典 SC 和 SC' 结构形成。晶粒间有限应变几何形状也系统地变化，尽管粘度的非线性和粘度对比之间存在权衡，导致相似的几何形状具有相当不同的机械行为。较硬相的有限旋转在任何一项实验中都是相似的。因此，原本平行的被动标记线在变形和旋转之后仍保持近平行，这可能会被误认为未旋转。内部变形性和晶粒之间的相互作用允许形成亚稳定晶粒伸长方向，而无需额外考虑外部滑移表面。对于相同的初始粘度，初始颗粒几何形状和随后的颗粒相互作用的轻微变化导致最终颗粒形状的广泛变化。
We describe a series of 12 large-strain, two-dimensional simple shear numerical experiments on two-phase linear and non-linear viscous materials. The modal percentage of the two-phases, their relative viscosities and the stress exponent of the dependence of viscosity on stress were systematically varied, allowing us to observe the effects of these parameters on the flow behaviour of the system. All experiments exhibited localisation, but the extent and type of localisation varied considerably, and the range of parameters allows both classical SC as well as SC′ structures to form. The inter-granular finite strain geometries also varied systematically, although there is a tradeoff between non-linearity of viscosity and the viscosity contrast that results in similar geometries for quite different mechanical behaviour. The finite rotation of the harder phases was similar within any one experiment. Originally parallel passive marker lines thus remain sub-parallel after deformation and rotation, which may be mistaken for non-rotation. The internal deformability and interaction between grains allows meta-stable grain elongation orientations to form, without any additional consideration of external slip surfaces. The slight variability of initial grain geometry and subsequent grain interactions leads to a wide variability in final grain shapes, for the same initial viscosities.