Concurrent atomistic and continuum simulation of strontium titanate
Concurrent atomistic and continuum simulation of strontium titanate
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DOI：
10.1016/j.actamat.2012.09.032
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发表时间：
2013
期刊：
影响因子：
9.4
通讯作者：
S. Yang;Liming Xiong;Q. Deng;Youping Chen
中科院分区：
文献类型：
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作者：
S. Yang;Liming Xiong;Q. Deng;Youping Chen
提出了一种并行原子-连续介质方法（CAC）来模拟复杂晶体中位错的形核和迁移以及裂纹的萌生和扩展的动力学过程。相对于分子动力学（MD）的方法，通过模拟的动态断裂过程中钛酸锶的拉伸和剪切载荷的组合和纳米压痕下的位错行为的准确性和效率的方法进行测试。CAC模拟结果表明，裂纹和位错顺利通过原子连续界面，而不需要额外的本构规则或特殊的数值处理。虽然在CAC模拟中由于自由度减少了98.4%而损失了一些精度，但所有CAC结果在定性和定量上与MD结果相当。CAC模拟中测得的层错宽度和纳米压痕硬度与现有的实验数据吻合良好。验证了离子材料中解理和滑移的准则。确认了在多原子晶体材料的并行原子连续方法中包括原子的内部自由度的必要性。
This paper presents a concurrent atomistic–continuum methodology (CAC) to simulate the dynamic processes of dislocation nucleation and migration as well as crack initiation and propagation in complex crystals. The accuracy and efficiency of the method is tested with respect to the molecular dynamics (MD) method through simulations of the dynamic fracture processes in strontium titanate under a combination of tension and shear loading and the dislocation behavior under nanoindentation. CAC simulation results demonstrated a smooth passage of cracks and dislocations through the atomistic–continuum interface without the need for additional constitutive rules or special numerical treatment. Although some accuracy is lost in CAC simulations as a consequence of a 98.4% reduction in the degrees of freedom, all the CAC results are qualitatively and quantitatively comparable with MD results. The stacking fault width and nanoindentation hardness measured in the CAC simulations agrees well with existing experimental data. Criteria for cleavage and slip in ionic materials are verified. The need to include the internal degrees of freedom of atoms in concurrent atomistic–continuum methods for polyatomic crystalline materials is confirmed.