Microscopic Fracture Mechanics Study on Mechanisms of Small Fatigue Crack Propagation by Micro Beam X-ray Stress Evaluation

微观断裂力学研究微束X射线应力评估小疲劳裂纹扩展机制

• 批准号: 13305011
• 负责人: TANAKA Keisuke
• 金额: $ 32.03万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13305011/
• 关键词: Fatigue; Crack; Composites; X-ray stress measurement; Fracture mechanics; Microbeamn X-rays; Fracture mechanisms; Micromechanics; 微視機構

1. A new system of microbeam stress measurement was developed by using a high intensity X-ray generator and a position sensitive detector. The stress in the area of about 100 μm was measured with a high precision by the new system. The system was also used to measure the in-plane stress in the surface region of thin films with submicrometer thickness.2. With the use of a high intensity X-rays from a synchrotron source, SPring-8, the stresses in the near crack-tip region in steel, ceramics and composites were successfully measured and used to predict the propagation behavior of cracks.3. Using electron back scattering pattern and atomic force microscopy, the crystallographic condition of fatigue crack initiation in fine-grained steels is proposed. In the early stage of fatigue crack propagation, the crack deflection and branching increase the resistance of crack propagation.4. The crack deflection and branching induce the fatigue crack closure level, and the crack propagation rate was a unique function of the effective stress intensity factor range.5. The effects of the grain boundaries and second phase on fatigue crack propagation was modeled by the blocked slip band near the crack tip. The crack closure is further included in the model. The relative role of microstructural barriers and crack closure on the threshold condition of small fatigue cracks were calarified.6. The effect of mixed mode loading on the fatigue crack propagation behavior was studied by using a precracked hollow cylinder under mixed torsional and axial loading. The fatigue crack propagation direction is controlled by the maximum range of tangential stress near the crack tip.

1。通过使用高强度X射线发生器和位置敏感探测器开发了一种新的微束应力测量系统。新系统以高精度测量了约100μm面积的应力。该系统还用于测量具有亚微米厚度的薄膜表面区域中的平面应力。2。通过从同步加速器源（Spring-8）中使用高强度X射线，成功测量了钢，陶瓷和组成的近裂纹尖端区域的应力，并用于预测裂纹的传播行为。3。使用电子背部散射模式和原子力显微镜，提出了细粒钢中疲劳裂纹启动的晶体学条件。在疲劳裂纹繁殖的早期，裂纹失败和分支增加了裂纹传播的抗性4。裂纹失败和分支会引起疲劳裂纹闭合水平，裂纹的传播速率是有效应力强度因子范围的独特功能。5。晶界和第二阶段对疲劳裂纹繁殖的影响是由裂纹尖端附近的阻塞带状带模型的。裂纹封闭进一步包括在模型中。微观结构屏障和裂纹闭合在小疲劳裂纹的阈值条件上的相对作用被造成了灾难。6。混合模式载荷对疲劳裂纹传播行为的影响是通过在混合扭转和轴向载荷下使用的前置空心缸进行研究的。疲劳裂纹的传播方向由裂纹尖端附近的切向应力的最大范围控制。

项目成果

Keisuke Tanaka: "Fatigue Crack Propagation from a Pre-Crack under Combined Torsional and Axial Loading"Proceedings of Advanced Technology in Experimental Mechanics, ATEM03. OS11W0458 (2003)

Keisuke Tanaka：“扭转和轴向联合载荷下预裂纹的疲劳裂纹扩展”实验力学先进技术论文集，ATEM03。

Hidehiko Kimura: "Atomic Force Microscopic Observation of Fatigue Crack Initiation in Ultrafine-Grained Steel"Material Science Research International. STP No.1. 117-122 (2001)

Hidehiko Kimura：“超细晶粒钢疲劳裂纹萌生的原子力显微镜观察”材料科学研究国际。

Yoshiaki Akiniwa: "Analysis of Crack Closure Behavior of Small Fatigue Cracks Interacting with Grain Structure"Material Science Research International. STP No.1. 64-69 (2001)

Yoshiaki Akiniwa：“与晶粒结构相互作用的小疲劳裂纹的裂纹闭合行为分析”国际材料科学研究。

Keisuke Tanaka: "Modeling of fatigue Crack Growth : Mechanistic Models"Comprehensive Structural Integrity. 4. 207-217 (2003)

Keisuke Tanaka：“疲劳裂纹扩展建模：机械模型”综合结构完整性。

Yuuya Yoshida: "Fatigue Crack Propagation and Stress-Induced Martensitic Transformation Behavior in TiNi"Proceedings of Advanced Technology in Experimental Mechanics, ATEM03. GSW0439 (2003)

Yuuya Yoshida：“TiNi 中的疲劳裂纹扩展和应力诱导马氏体相变行为”实验力学先进技术论文集，ATEM03。