共查询到18条相似文献,搜索用时 46 毫秒
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分子动力学模拟金属纳米杆 总被引:1,自引:1,他引:1
纳米结构(包括纳米杆)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为的有效方法,采用EAM势模拟金属铜纳米杆在轴向压力作用下的力学行为,结果表明,当外力较小时,纳米杆受压发生纵向收缩;当外力达到某一临界值时,纳米杆发生横向弯曲(即屈曲)行为;稳定的弯曲状态能继承受外载,当外力继续增大时,纳米杆发生倾覆而失效。 相似文献
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纳米晶铜单向拉伸变形的分子动力学模拟 总被引:13,自引:0,他引:13
纳米材料是由尺度在1-100nm的微小颗粒组成的体系,由于它具有独特的性能而备受关注。本文简要地回顾了分子动力学在纳米材料研究中的应用,并运用它模拟了平均晶粒尺寸从1.79-5.38nm的纳米晶体的力学性质。模拟结果显示:随着晶粒尺寸的减小,系统与晶粒内部的原子平均能量升高,而晶界上则有所下降;纳米晶体的弹性模量要小于普通多晶体,并随着晶粒尺寸的减小而减小;纳米晶铜的强度随着晶粒的减小而减小,显示了反常的Hall-Petch效应;纳米晶体的塑性变形主要是通过晶界滑移与运动,以及晶粒的转动来实现的;位错运动起着次要的、有限的作用;在较大的应变下(约大于5%),位错运动开始起作用;这种作用随着晶粒尺寸的增加而愈加明显。 相似文献
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分子动力学模拟的冷冻原子法 总被引:3,自引:0,他引:3
通过分析分子动力学过程粒子运动的基本特征,提出分离不同性质、不同量级的原子快运动和慢运动进行模拟的思想,建立了适用于这两种运动弱耦合情况的冷冻原子方法,该方法可使分子动力学模拟收敛速度有明显改善.并能得到更为精确的结果. 相似文献
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分子沉积膜纳米压痕过程的分子动力学模拟 总被引:2,自引:0,他引:2
在利用联合原子模型并考虑静电力作用的基础上,采用分子动力学模拟方法研究了金探针作用下分子沉积膜的纳米压痕过程,并对其纳米力学行为进行了理论分析.结果表明,分子沉积膜在探针压下过程中出现了明显的接触跳跃现象,探针下面的膜的分子倾角和法向载荷呈现出相同的滞后趋势,这可能是探针和分子沉积膜之间粘着力作用的结果. 相似文献
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自组装膜纳米压痕的分子动力学模拟 总被引:1,自引:0,他引:1
研究了金探针对沉积在金 (111)表面的 CH3 (CH2 ) 1 5S自组装膜的纳米压痕的分子动力学模拟 .结果表明 ,自组装膜在金探针的作用下出现了跳跃接触现象 ,倾角和法向载荷都出现明显的滞后 ,并进一步表明与探针和膜之间的粘着力有关 相似文献
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晶界也是一种界面。表面张力是晶界的一个重要的热力学量。本文采用计算机分子动力学模拟(CMD)方法计算 α-Fe,∑=9 的晶界在不同温度和压力下的表面张力,结果与实验值的比较是满意的。发现熵对晶界的表面张力的贡献是很小的,通常可以忽略不计。 相似文献
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The stress-strain behavior and copper are studied by the molecular dynamics incipient yield surface of nanoporous single crystal (MD) method. The problem is modeled by a periodic unit cell subject to multi-axial loading. The loading induced defect evolution is explored. The incipient yield surfaces are found to be tension-compression asymmetric. For a given void volume fraction, apparent size effects in the yield surface are predicted: the smaller behaves stronger. The evolution pattern of defects (i.e., dislocation and stacking faults) is insensitive to the model size and void volume fraction. However, it is loading path dependent. Squared prismatic dislocation loops dominate the incipient yielding under hydrostatic tension while stacking-faults are the primary defects for hydrostatic compression and uniaxial tension/compression. 相似文献
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本文利用分子动力学计算机模拟的方法,研究了氪的固-液、液-气和气-固的界面现象。显示了液体的零级径向分布是有序的,与固体相邻的液体部分有类晶结构,固体表面出现了气体吸附层。表面张力计算结果与实验值很好的吻合,证明Lennead-Jones势对球形原子的相互作用作了很好的描述,在表面张力计算中可以忽略去截断效应。 相似文献
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Fengchao Wang Yapu Zhao State 《Acta Mechanica Solida Sinica》2011,24(2):101-116
The properties of the confined liquid are dramatically different from those of the bulk state, which were reviewed in the present work. We performed large-scale molecular dynamics simulations and full-atom nonequilibrium molecular dynamics simulations to investigate the shear response of the confined simple liquid as well as the n-hexadecane ultrathin films. The shear viscosity of the confined simple liquid increases with the decrease of the film thickness. Apart from the well-known ordered structure, the confined n-hexadecane exhibited a transition from 7 layers to 6 in our simulations while undergoing an increasing shear velocity. Various slip regimes of the confined n-hexadecane were obtained. Viscosity coefficients of individual layers were examined and the results revealed that the local viscosity coefficient varies with the distance from the wall. The individual n-hexadecane layers showed the shear-thinning behaviors which can be correlated with the occurrence of the slip. This study aimed at elucidating the detailed shear response of the confined liquid and may be used in the design and application of micro- and nano-devices. 相似文献
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温度和加载速率影响位错发射的分子动力学模拟 总被引:2,自引:2,他引:0
以A1作为研究对象,采用EAM势进行分子动力学模拟,在Ⅰ型和Ⅱ型加载条件下,研究了温度和取向对发射位错的临界应力强度因子的影响,模拟结果表明,裂尖发射位错的监介应力强度因子随温度升高指数规律降低,但却随加载速率的增大而升高。 相似文献
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The interfacial molecular structure of materials with different lattice constants is simulated by using the method of molecular dynamics (MD). Potential of modified analytical embedded atom method (MAEAM) is used for nominterfacial atoms. To simulate the state of interracial atoms, further modifications are applied to the MAEAM potential based on the first- principle simulation results. It is concluded that a small change of potential may greatly influence the interfacial molecular structure. Void and diffusions can be observed in the simulation results. It is also found that the pre-existed dot defects before bonding can decrease the number of interfacial defects greatly, thereby, can increase the strength of the interface. 相似文献