Concurrent atomistic–continuum simulation of polycrystalline strontium titanate
Concurrent atomistic–continuum simulation of polycrystalline strontium titanate
复制标题
多晶钛酸锶的并行原子连续模拟
DOI：
10.1080/14786435.2015.1076178
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发表时间：
2015
影响因子：
1.6
通讯作者：
Youping Chen
中科院分区：
文献类型：
--
作者：
Shengfeng Yang;Ning Zhang;Youping Chen
本文介绍了并行原子连续体（CAC）方法在模拟多晶多原子材料缺陷动态演化方面的新发展。 CAC 方法基于一种理论表述，该理论表述将 Kirkwood 的传输过程统计力学理论扩展到晶体材料的多尺度描述。它解决了晶格单元的变形和每个晶格单元内的内部变形，使其成为模拟多原子材料的合适方法。这项工作的模拟结果表明，CAC 可以模拟原子分辨晶界 (GB) 区域的位错和裂纹的成核，以及随后传播到多晶钛酸锶中的粗网格晶粒内部，而无需补充本构方程或额外的数值处理。由于计算成本显着降低，CAC 不仅可以预测晶界结构，还可以预测位错、裂纹和晶界的动态行为，所有这些都可以与原子级分子动力学模拟获得的结果相媲美。模拟结果还表明，位错往往从晶界和三重连接处开始。滑移面和晶界面之间的角度在确定晶界位错反应中起着关键作用。
This paper presents the new development of a concurrent atomistic–continuum (CAC) method in simulation of the dynamic evolution of defects in polycrystalline polyatomic materials. The CAC method is based on a theoretical formulation that extends Kirkwood’s statistical mechanical theory of transport processes to a multiscale description of crystalline materials. It solves for both the deformation of lattice cells and the internal deformation within each lattice cell, making it a suitable method for simulations of polyatomic materials. The simulation results of this work demonstrate that CAC can simulate the nucleation of dislocations and cracks from atomistically resolved grain boundary (GB) regions and the subsequent propagation into coarsely meshed grain interiors in polycrystalline strontium titanate without the need of supplemental constitutive equations or additional numerical treatments. With a significantly reduced computational cost, CAC predicts not only the GB structures, but also the dynamic behaviour of dislocations, cracks and GBs, all of which are comparable with those obtained from atomic-level molecular dynamics simulations. Simulation results also show that dislocations tend to initiate from GBs and triple junctions. The angle between the slip planes and the GB planes plays a key role in determining the GB-dislocation reactions.