STUDY ON THE CONSTRAINT EFFECT USING THE DAMAGE MECHANICS APPROACH.

使用损伤力学方法研究约束效应。

• 批准号: 09650119
• 负责人: KIKUCHI Masanori
• 金额: $ 1.92万
• 依托单位: SCIENCE UNIVERSITY OF TOKYO
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650119/
• 关键词: Constraint effect; Dimple fracture; Damage mechanics; Stress triaxiality; Finite Element Method; 拘束効果; 有限原素法; 延性破壊; ボイド率; 損傷解析

(1) By changing the constraint condition, fracture toughness tests are conducted. The fracture toughness value, which is a macroscopic parameter, is affected by the constraint condition. By the observation of fracture surface using scanning electron microscope(SEM), it was shown that the microscopic parameter such as dimple diameter, dimple number and power value are also affected by the constraint condition largely.(2) The dimple fracture tests of notched specimen with different notch radius are conducted. The fracture surface observation showed that the stress triaxiality also affects the dimple fracture process strongly. The change of the stress triaxiality means the change of the constraint condition. Precise measurement of the dimple diameter and dimple aspect ratio is made, and more than 3000 data are obtained. It is base of the data-base on this research area.(3) The dimple fracture simulation is conducted using FEM considering the damage mechanics effect. Two kinds of tests described in (1) and (2) are simulated using this code. It is shown that the constraint effect was evaluated well. The effect of the non-uniform distributions of inclusions in the base matrix can be considered using this code. It became obvious that the non-uniform distribution of inclusions affects the dimple fracture pattern largely.(4) As a result, the relation between the constraint condition and the microscopic ductile fracture process is becoming clear, which is the basis of the study on the constraint condition from the microscopic fracture mechanics.

（1）通过改变约束条件，进行了断裂韧性测试。断裂韧性值是宏观参数，受约束条件的影响。通过使用扫描电子显微镜观察断裂表面（SEM），表明显微镜参数（例如凹痕直径，凹痕数和功率值）也受约束条件的影响。（2）（2）凹口骨折测试的凹口骨折测试进行了不同的槽口半径。断裂表面观察表明，应力三轴性也会强烈影响凹痕过程。应力三轴性的变化意味着约束条件的变化。制作了Dimple直径和Dimple纵横比的精确测量，并获得了3000多个数据。它是该研究领域的数据库的基础。（3）使用FEM考虑损坏力学效应，进行了Dimple断裂模拟。使用此代码模拟了（1）和（2）中描述的两种测试。结果表明，约束效应得到了很好的评估。可以使用此代码来考虑基础基质中包含物的不均匀分布的影响。很明显，包含物的不均匀分布会影响凹痕骨折模式。（4）结果，约束条件与微观延性断裂过程之间的关系越来越明显，这是研究的基础，这是研究的基础。微观断裂力学的约束条件。