Realisation of 3D In-situ Assessment of Local Crack Driving Forces via Ultra-high Resolution Synchrotron Xray CT

通过超高分辨率同步加速器X射线CT实现局部裂纹驱动力的3D原位评估

• 批准号: 15206076
• 负责人: KOBAYASHI Toshiro
• 金额: $ 16.22万
• 依托单位: Toyohashi University of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15206076/
• 关键词: Fracture toughness; Impact fracture; Metallic materials; Thermally-activated process; Hopkinson bar technique; Material testing procedure; IF steel; 6000-series aluminum alloys; ひずみゲージ; Al-Mg系合金; Al-Mg-Si合金; 衝撃引張試験; 応力波; 有限要素法解析; ひずみ速度依存性

Impact safety of transport machines strongly depends on materials themselves. Recently, due to light-weightening of machines, since materials behaviors include inherent impact phenomena, it is strongly required for their evaluation to have mechanical consideration and expertise different from usual materials tests. Various properties data under high strain rate loading, which are available in the current literature, seem to be doubtful in its accuracy. Strength and structural analyses based on uncertain data give the least reliability. In the present study, mainly within the range of monotonic tensile test and fracture toughness test of materials, it has been investigated on the measuring procedures of load and strain. Especially, how to measure mechanical properties is shown for anyone using any testing machines for any materials over a wide temperature range. Also, how to measure accurately is shown as forms of easy standards for operators of testing machines without expertise.Concre … More tely speaking, as model materials for steels and non-ferrous metals, IF steels and 6000-series aluminum alloys were used. These two alloys have been extensively used for bodies and bumpers of automobiles in which the highest safety is required in our country as mechanical structures. Testing conditions and issues on accuracy have been clarified when these materials are tested. Using valid and accurate impact property data for the materials which cover wide ranges of temperature and rate between static and high speed conditions, constitutive equations under impact loading for plastic deformation of metallic materials, which have been matters of controversy for a long time, has been checked for a wide strain rate range. Strain-rate dependency of materials properties and strain rate history effects have been also re-arranged and investigated theoretically. In addition, not only providing materials test methods and test data which can contribute practically to impact safety of transport machines and reliability assurance, but also helping fundamental interpretation of materials deformation behaviors, this research area has been summed up academically within the 20^<th> century. Less

运输机械的冲击安全性很大程度上取决于材料本身。近年来，由于机械的轻量化，由于材料的行为包含固有的冲击现象，因此对其评价强烈要求有不同于通常材料试验的力学考虑和专业知识。目前文献中提供的高应变率加载下的各种性能数据，其准确性似乎是值得怀疑的。基于不确定数据的强度和结构分析给出的可靠性最低。本文主要从材料的单调拉伸试验和断裂韧性试验两个方面，对载荷和应变的测量方法进行了研究。特别是，向任何人展示了如何在宽温度范围内使用任何材料的任何试验机来测量机械性能。此外，对于没有专业知识的试验机操作员来说，如何准确测量也是一种简单的标准。Concre…更确切地说，作为钢和有色金属的模型材料，使用了IF钢和6000系列铝合金。这两种合金作为机械结构被广泛应用于我国安全性要求最高的汽车车身和保险杠上。在对这些材料进行测试时，测试条件和准确性问题已得到澄清。利用材料在静态和高速条件下较宽的温度和速率范围内的有效和准确的冲击性能数据，对长期以来存在争议的金属材料塑性变形的冲击加载本构方程在较大的应变率范围内进行了校核。对材料性能的应变率依赖性和应变率历史效应也进行了重新安排和理论研究。此外，为了给运输机械的安全性和可靠性保证提供实用的材料试验方法和试验数据，也有助于从根本上解释材料的变形行为，这一研究领域在20世纪内已经形成了学术总结。较少

项目成果

T.Masuda, T.Kobayashi, L.Wang, H.Toda: "Effects of strain rate on deformation behavior of A6061-T6 aluminum alloys"Materials Science Forum. 426-432. 285-290 (2003)

T.Masuda、T.Kobayashi、L.Wang、H.Toda：“应变率对 A6061-T6 铝合金变形行为的影响”材料科学论坛。

T.Kobayashi: "Strength and Toughness of Materials"Springer - Verlag. 275 (2004)

T.Kobayashi：“材料的强度和韧性”Springer - Verlag。

Progress in visualization technique : Application of local internal mechanical quantities inside the materials to in-situ

可视化技术进展：材料内部局部力学量在原位应用

• 发表时间: 2004
• 期刊: Material Testing Technique vol.48
• 作者: H.Toda;T.Kobayashi;T.Ohgaki
• 通讯作者: T.Ohgaki

T.Kobayashi: "Strength and Fracture of Aluminium Alloys"Materials Science Forum. (印刷中). (2004)

T.Kobayashi：“铝合金的强度和断裂”材料科学论坛（出版中）。

S.Morita, T.Kobayashi: "Ductile-Brittle Transition Behaviours with Two Striker Geometries in the Instrumented Charpy Impact Test"Materials Science Forum. (印刷中). (2004)

S.Morita、T.Kobayashi：“仪器化夏比冲击试验中两种冲击器几何形状的延性-脆性转变行为”材料科学论坛（2004 年）。