论文标题
动态长度尺度和晶体可塑性中最弱的链接行为
Dynamic Length Scale and Weakest Link Behavior in Crystal Plasticity
论文作者
论文摘要
异质固体结构的塑性变形通常以随机间歇性局部塑料事件为特征。在中尺度上，此特征可以通过空间波动的局部收益阈值表示。在这里，我们研究了这种方法的有效性和根据离散脱位模型的晶体可塑性大小的理想选择。我们发现，如果引入淬灭的短距离相互作用，则代表塑料活动来源的链接数量表现出异常（超扩张）缩放（通常以最弱的链接模型中的假定）。原因是，远程脱位相互作用与短程淬火障碍之间的相互作用破坏了无标度的动态相关性，导致事件定位的特征长度尺度。提出了几种方法来确定可以推广到其他类型的异质材料的动态长度尺度。
Plastic deformation of heterogeneous solid structures is often characterized by random intermittent local plastic events. On the mesoscale this feature can be represented by a spatially fluctuating local yield threshold. Here we study the validity of such an approach and the ideal choice for the size of the representative volume element for crystal plasticity in terms of a discrete dislocation model. We find that the number of links representing possible sources of plastic activity exhibits anomalous (super-extensive) scaling which tends to extensive scaling (often assumed in weakest-link models) if quenched short-range interactions are introduced. The reason is that the interplay between long-range dislocation interactions and short-range quenched disorder destroys scale-free dynamical correlations leading to event localization with a characteristic length-scale. Several methods are presented to determine the dynamic length-scale that can be generalized to other types of heterogeneous materials.
