Hierarchical Modeling of Crystal Deformation

小行星9971922 在材料的热物理性质的分析中，一组重要的问题围绕着如何将这种分析基于对材料内发生的潜在缺陷机制的理解的问题。 例如，在塑性变形的背景下，虽然众所周知，塑性通常是由位错的运动介导的，但到目前为止，直接基于位错物理学构建塑性模型的目标在很大程度上尚未实现。 部分原因是，在这类多长度和时间尺度的问题中的运算。 这里提出的工作有两个关键的推力：1）新的计算工具的发展，调查的问题，涉及一个层次的长度和时间尺度和2）这些层次的工具的应用程序的成核，运动和位错的相互作用的分析。 我们的方法论工作将集中在扩展的准连续体方法，以三维进行动态模拟在有限的温度下，包括网格细化和网格粗化的全面能力。 这些思想在位错物理学中的应用将包括位错运动的动力学分析和结的强度

9971922Phillips An important set of problems in the analysis of the thermophysical properties of materials surround the question of how to base this analysis on an understanding of the underlying defect mechanisms taking place within a material. For example, in the context of plastic deformation, though it is well known that plasticity is often mediated by the motion of dislocations, as yet, the goal of constructing models of plasticity based directly on the physics of dislocations has been largely unfulfilled. Part of the reason for this is the operation in problems of this sort of multiple length and time scales. The work proposed here has two key thrusts: 1) the development of new computational tools for the investigation of problems involving a hierarchy of length and time scales and 2) the application of these hierarchical tools to the analysis of the nucleation, motion and interaction of dislocations. Our methodological work will center on the extension of the quasicontinuum method to three-dimensions with a full capability for carrying out dynamical simulations at finite temperature and including both mesh refinement and mesh coarsening. The application of these ideas to the physics of dislocations will include an analysis of the kinetics of dislocation motion and the strength of junctions