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Orientation and Rate Dependence of Wave Propagation in Shocked Beta-SiC from Atomistic Simulations 下载免费PDF全文
The orientation dependence of planar wave propagation in beta-SiC is studied via the molecular dynamics (MD) method. Simulations are implemented under impact loadings in four main crystal directions, i.e., (lO0), (llO), 〈111〉, and 〈112}. The dispersion of stress states in different directions increases with rising impact velocity, which implies the anisotropic characteristic of shock wave propagation for beta-SiC materials. We also obtain the Hugoniot relations between the shock wave velocity and the impact velocity, and find that the shock velocity falls into a plateau above a threshold of impact velocity. The shock velocity of the plateaux is dependent on the shock directions, while 〈111} and 〈112/ can be regarded as equivalent directions as they almost reach the same plateau. A comparison between the atomic stress from MD and the stress from Rankine-Hugoniot jump conditions is also made, and it is found that they agree with each other very well. 相似文献
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纳米结构的力学性能是纳米超微型器件设计的基础,分子动力学是研究纳米结构力学行为的有效方法.本文采用镶嵌原子方法模拟金属铜纳米棒的弯曲力学行为.计算结果表明由于尺寸效应和表面效应的影响,在纳观尺度下纳米结构表现出与宏观尺度下完全不同的力学特征.金属纳米棒弯曲力学过程分为初始变形迟滞阶段、线弹性变形阶段和塑性变形阶段.塑性变形阶段表现出“刚化”、“台阶”和较强的延性等特征.
关键词:
纳米结构
纳米棒
弯曲性能
分子动力学 相似文献
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