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The formation and mechanical properties of amorphous copper are studied using molecular dynamics simulation. The simulations of tension and shearing show that more pronounced plasticity is found under shearing, compared to tension. Apparent strain hardening and strain rate effect are observed. Interestingly, the variations of number density of atoms during deformation indicate free volume creation, especially under higher strain rate. In particular, it is found that shear induced dilatation does appear in the amorphous metal. 相似文献
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A closed, trans-scale formulation of damage evolution based on the statistical microdamage mechanics is summarized in this
paper. The dynamic function of damage bridges the mesoscopic and macroscopic evolution of damage. The spallation in an aluminium
plate is studied with this formulation. It is found that the damage evolution is governed by several dimensionless parameters,
i.e., imposed Deborah numbersDe
* andDe, Mach numberM and damage numberS. In particular, the most critical mode of the macroscopic damage evolution, i.e., the damage localization, is determined
by Deborah numberDe
*. Deborah numberDe
* reflects the coupling and competition between the macroscopic loading and the microdamage growth. Therefore, our results
reveal the multi-scale nature of spallation. In fact, the damage localization results from the nonlinearity of the microdamage
growth. In addition, the dependence of the damage rate on imposed Deborah numbersDe
* andDe, Mach numberM and damage numberS is discussed.
The project supported by the National Natural Science Foundation of China (10172084, 10232040, 10232050, 10372012, 10302029)
and the Special Funds for Major State Research Project (G200077305) 相似文献
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固体的统计细观力学——-连接多个耦合的时空尺度 总被引:10,自引:2,他引:10
从固体力学所面临的新的挑战------多物理、多尺度耦合及其现状的描述开始, 以层裂
过程为例, 说明了这些多尺度非平衡问题的基本困难在于, 在固体中不同尺度上有不同的微
结构层次及不同的演化物理和速率. 接下来, 概述了一些针对这一困难的独特的思路及
其成果. 第3部分强调了一些统计平均方法的范式, 以及处理包含多个时间和空间尺度的问
题的新思路, 特别是非平衡损伤演化导致宏观失效的问题. 在第4部分, 简要评述了一些连
接多个空间和时间尺度的细观力学框架, 如位错理论, 物理细观力学, Weibull理论, 随机
理论等, 并且阐述了其中蕴含的跨尺度耦合的机理. 然后, 在第5部分, 回到了描述损
伤演化过程的框架, 也就是统计细观损伤力学以及它的跨尺度封闭近似. 基于这些跨尺度框
架, 在第6部分, 对控制跨尺度耦合的可能机理进行了评述和比较. 由于对失效时灾变
的洞察与跨尺度强耦合紧密相关, 一些非平衡和强相互作用的新概念在第7部分进行了讨
论. 最后, 以一个简短的总结和一些建议结束. 相似文献
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