Research on Strength Evaluation of Crystalline Metal Based on Molecular Dynamics Simulation

基于分子动力学模拟的晶体金属强度评价研究

• 批准号: 04452122
• 负责人: KITAGAWA Hiroshi
• 金额: $ 4.48万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1993
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04452122/
• 关键词: Molecular Dynamics; Polycrystalline Metal; Computer Simulation; Fracture Strength; ab initio Calculation; dislocation Motion; Cryatal Plasticiy; Crack Propation; 材料強度評価; 分子軌道計算; バンド構造解析; 数値シミュレーション; 第一原理解析; 走査型トンネル顕微鏡

Fundamental phenomena governing the fracture processes appearing in a polycrystalline metal are studied by means of computer simulation using both atomic and continuum models. The main results obtained are summarized as follows :(1) Molecular dynamics simulations are performed for fcc-Cu and bcc-Fe single crystals and the following fundamental phenomena governing the material strength properties are examined ; a) crack initiation mechanisms activated by interaction of the dislocation and deformation twin, b) dynamical characters of the atomic structure in near-chip region under the modes I,II and III loading, especially dependence of the crystal orientation and temperature on the dislocation emission leading to the ductile fracture,c) interaction between the grain boundary and lattice defects, and d) the self-diffusion properties and its temperature dependence in the grain boundary region.(2) Using the continuum model derived from the crystal plasticity theory, the finite element analysis of the ductile crack is carried on and meaning of microscopic stress and micro-mechanism of shear-band formation is examined, regarding the simulation results obtain from the atomic model as a substantial data for the microscopic fracture process.(3) In order to evaluate the appropriateness and limit of its validity, ab initio analysis based on super-cell method and/or molecular orbital method are performed.

本文采用原子模型和连续介质模型，通过计算机模拟研究了多晶金属断裂过程的基本现象。（1）对fcc-Cu和bcc-Fe单晶进行了分子动力学模拟，研究了影响材料强度特性的基本现象; a）位错与形变孪晶相互作用激活的裂纹萌生机制，B）Ⅰ、Ⅱ、Ⅲ型加载下近晶区原子结构的动力学特征，特别是晶体取向和温度对导致韧性断裂的位错发射的依赖性，c）晶界和晶格缺陷之间的相互作用，以及d）晶界区域中的自扩散性质及其温度依赖性。(2)利用晶体塑性理论推导出的连续介质模型，对韧性裂纹进行了有限元分析，探讨了微观应力的含义和剪切带形成的微观机制，并将原子模型获得的模拟结果作为微观断裂过程的大量数据。(3)为了评估其有效性的适当性和限度，基于超晶胞方法和/或分子轨道方法进行从头算分析。

项目成果

Kitagawa,H.Nakatani,A.: "“Microstructural Aspects of Crack Extension in a Crystalline Material(A Molecular Dynamic Study)"," Mechanical Behaviour of Materials-VI(ed.by Jono,M.and Inoue,T.)Proceedings of the Sixth International Conference,Kyoto,Japan,29 Ju

Kitakawa, H. Nakatani, A.：““结晶材料中裂纹扩展的微观结构方面（分子动力学研究）”，材料机械行为-VI（Jono, M. 和 Inoue, T. 编辑）论文集第六届国际会议，日本京都，29 月

北川 浩・中谷彰宏: "結晶構造体に対する計算力学モデルの検討([II]面外せん断荷重下のき裂先端の微視的変形場の分子動力学シミュレーション)" 日本機械学会論文集 A編. 59. 256-262 (1993)

Hiroshi Kitakawa 和 Akihiro Nakatani：“晶体结构计算力学模型的研究（[II]面外剪切载荷下裂纹尖端微观变形场的分子动力学模拟）” 日本机械工程学会会刊，A 卷. 59. 256-262 (1993)

Kitagawa,H.,Nakatani,A.,and Shibutani,Y.: "“Molecular Dynamics Study of Crack Initiation"" Proceedings of IMMM'93(ed.by Tokuda,M.and Senoo,M.),International Seminar on Microstructures and Mechanical Properties of New Engineering Materials,Mie University,.

Kitakawa, H.、Nakatani, A. 和 Shibutani, Y.：““裂纹引发的分子动力学研究””IMMM93 论文集（由 Tokuda, M. 和 Senoo, M. 编辑），国际微观结构研讨会.新工程材料的机械性能，三重大学，。

北川 浩 中谷 彰宏: "結晶講造体に対する計算力学モデルの検討[II]面外せん断荷重下のき裂先端の微視的変形場の分子動力学シミュレーション" 日本機械学会論文集(A編). 59. 256-262 (1993)

Hiroshi Kitakawa 和 Akihiro Nakatani：“晶体结构计算力学模型的研究[II]面外剪切载荷下裂纹尖端微观变形场的分子动力学模拟”日本机械工程师学会会议录（编辑） . 59. 256-262 (1993)。

Kitagawa,H.Nakatani,A.: "“Crystal Plasticity Model and Molecular Dynamics(Numerical Simulation of Plane Strain Inhomogeneous Deformation)"" Constitutive Relations for Finite Deformation of Polycrystalline Metals(ed.by Wang,R.and Drucker,D.C.),Proceedings

Kitakawa, H.Nakatani, A.：“晶体塑性模型和分子动力学（平面应变不均匀变形的数值模拟）””多晶金属有限变形的本构关系（Wang,R.和 Drucker,D.C. 编辑），会议记录