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

• 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

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.

对小裂纹的疲劳阈值分析分析的弹性塑性分析：对分析溶液进行了分析解决方案，用于针对不可压缩的圆形圆柱体的局部和弥漫性分叉，受到轴对称载荷的影响，其组成型行为通过在强度塑料范围内描述了其组成型行为的描述。该分析包括剪切带形成，剪切带倾斜度，弥漫性屈曲形成以及与材料特性和应力相关的弥散屈曲模式的长和短波长限制的条件。提出的是，正常产物比描述了正常收益状态的方法程度，由于切向压力效应效应而导致的切向塑性应变速率和运动硬化可变影响局部和弥漫性分支的开始。FATIGUE和裂缝的局部和弥漫性：弹性区域的表征在弹性区域的表征混合了蓝光模式。通过在非常规可塑性框架内提出一个基于子加载表面概念的标准来描述出现在裂纹前沿处的变形区。据表明，混合模式裂纹沿弹性区域的最小值传播。进行了一项研究，以阐明位于有限裂纹附近的倾斜平面上的位错的行为。根据有限裂纹与裂纹尖端附近的脱位之间的相互作用提出了方程。使用扩展方程研究了裂纹长度对施加到位错的力的影响。

项目成果

Crack tip plasticity in edge-blunt-cracked plates

边缘钝裂板的裂纹尖端塑性

• 发表时间: 2005
• 期刊: McMat2005, Baton Rouge, Louisiana, USA, June 1-3 Paper No.464
• 作者: Khojastehpour;M.;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

• 发表时间: 2005
• 期刊: ICCES'05, Chennai, India, December 1-6 41
• 作者: Khojastehpour;M.;Murakami.Y;Hashiguchi.K.
• 通讯作者: Hashiguchi.K.

Localized bifurcation in soils with tangential plasticity

具有切向塑性的土壤中的局部分叉

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