| Project/Area Number |
04452122
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
材料力学
|
|---|
| Research Institution | Osaka University |
|---|
Principal Investigator |
KITAGAWA Hiroshi Osaka University, Department of Mechanical Engineering, Professor, 工学部, 教授 (30029095)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
NAKATANI Akihiro Osaka University, Department of Mechanical Engineering, Research Associate, 工学部, 助手 (50252606)
NAKAMACHI Eiji Osaka University, Department of Mechanical Engineering, Associate Professor, 工学部, 助教授 (60099893)
渋谷 陽二 大阪大学, 工学部, 助手 (70206150)
|
|---|
| Project Period (FY) |
1992 – 1993
|
| Project Status |
Completed (Fiscal Year 1993)
|
| Budget Amount *help |
¥7,000,000 (Direct Cost: ¥7,000,000)
Fiscal Year 1993: ¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1992: ¥4,900,000 (Direct Cost: ¥4,900,000)
|
|---|
| Keywords | 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 |
|---|
| Research Abstract |
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.
|
