标题： 有限应变晶体粘塑性中的变形带图案和位错结构 显示英文标题

标题： Deformation band patterns and dislocation structures in finite strain crystal viscoplasticity

摘要： 单晶中的变形带图案通过基于位错密度演化的有限应变晶体粘塑性模型进行研究。 在存在强隐含硬化和弱速率依赖性的条件下，变形组织形成由位错墙分隔的单滑移区域组成的层状微观结构。 在平面应变压缩下的二维单晶中，分析了材料和数值参数对这些图案的形核和形态的影响。 在无内在材料长度尺度的情况下，对受拉伸的三维单晶圆柱体进行观察，发现变形微观结构的特征尺寸取决于网格尺寸和边界条件。 为解决这一限制，引入了应变梯度塑性，提供了一个控制图案尺寸的长度尺度。 最后，我们证明变形图案和位错结构也出现在二维和三维多晶中，突显了该现象的普遍性。 显示英文摘要

摘要： Deformation band patterning in single crystals is investigated using a finite strain crystal viscoplasticity model based on the evolution of dislocation densities. In the presence of strong latent hardening and weak rate dependence, the deformation organizes into laminate microstructures consisting of single-slip regions separated by dislocation walls. The influence of material and numerical parameters on the nucleation and morphology of these patterns is analyzed in 2D single crystals under plane strain compression. Pattern formation is also observed in 3D single-crystal cylinders subjected to tension, where the characteristic size of deformation microstructures is found to depend on mesh size and boundary conditions in the absence of an intrinsic material length scale. To address this limitation, strain gradient plasticity is introduced, providing a length scale that governs the size of the patterns. Finally, we demonstrate that deformation patterns and dislocation structures also emerge in 2D and 3D polycrystals, highlighting the generality of the phenomenon.