材料の分岐変形に関する弾塑性変形解析と微小疲労き裂進展挙動解明への応用

分叉材料变形的弹塑性变形分析及其在阐明微疲劳裂纹扩展行为中的应用

基本信息

批准号：
04F04078
负责人：
村上敬宜
金额：
$ 1.54万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for JSPS Fellows
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-04F04078/
关键词：
Bifurcation and Instability Elastoplasticity Constitutive Behavior Elastoplastic Materials Subloading Surface Model Crack tip Plasticity Dislocation Mechanics Mixed Mode Fracture Shear Band Bifurcation

项目摘要

Elastoplastic analysis of bifurcation and application to fatigue threshold analysis of small cracksBifurcation :Analytical solutions are presented for the localized and diffuse bifurcations of an incompressible circular cylinder subjected to axisymmetric loading, whose constitutive behavior is described by adopting the tangential-subloading surface model falling within the framework of tangential plasticity. The analysis includes the conditions for shear band formation, shear band inclination, diffuse buckling formation, and the long and short wavelength limits of diffuse buckling modes in relation to material properties and stress. It becomes well-informed that the normal-yield ratio describing the degree of approach to the normal-yield state, the tangential-plastic strain rate due to the tangential-stress rate effect and the kinematic hardening variable influence the onset of localized and diffuse bifurcations.Fatigue and Fracture :The characterization of the elastoplastic zone at the tip of a blunt crack under mixed mode loading was discussed. The deformed zone appearing at the crack front is described by presenting a criterion based on the subloading surface concept falling within the framework of unconventional plasticity. It is revealed that the mixed mode crack propagates along the minimum value of the elastoplastic region.A study was conducted to clarify the behavior of a dislocation located on the inclined plane near a finite crack. Equations were presented for the forces based on the interactions between a finite crack and the dislocations near the crack tip. The influences of crack length on the forces applied to a dislocation were investigated using the extended equations.

分岔的弹塑性分析及其在小裂纹疲劳阈值分析中的应用分岔：提出了轴对称载荷作用下不可压缩圆柱体的局部分岔和扩散分岔的解析解，采用切向分加载表面模型描述了其本构行为。切向塑性框架。分析包括剪切带形成的条件、剪切带倾斜、扩散屈曲形成以及与材料特性和应力相关的扩散屈曲模式的长波长和短波长限制。众所周知，描述接近法向屈服状态程度的法向屈服比、由于切向应力率效应引起的切向塑性应变率和运动硬化变量影响局部和扩散分岔的发生疲劳和断裂：讨论了混合模式载荷下钝裂纹尖端弹塑性区的特征。通过提出基于非常规塑性框架内的次加载表面概念的准则来描述出现在裂纹前沿的变形区域。结果表明，混合模式裂纹沿着弹塑性区域的最小值扩展。进行了研究以阐明位于有限裂纹附近斜面上的位错的行为。基于有限裂纹和裂纹尖端附近位错之间的相互作用，提出了力的方程。使用扩展方程研究了裂纹长度对位错施加的力的影响。

项目成果

期刊论文数量（3）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Crack tip plasticity in edge-blunt-cracked plates

边缘钝裂板的裂纹尖端塑性

DOI：
发表时间：
2005
期刊：
McMat2005, Baton Rouge, Louisiana, USA, June 1-3 Paper No.464
影响因子：
0
作者：
Khojastehpour;M.;Murakami.Y.
通讯作者：
Murakami.Y.

Localized bifurcation in soils with tangential plasticity

具有切向塑性的土壤中的局部分叉

DOI：
发表时间：
2004
期刊：
The 39th Japan National Conference on Geotechnical Engineering, Niigata, Japan, July 6-9
影响因子：
0
作者：
Khojastehpour;M.;Hashiguchi.K.;Murakami.Y.
通讯作者：
Murakami.Y.

Elastoplastic zone and crack initiation in blunt-notched plates

钝缺口板的弹塑性区和裂纹萌生