DEVELOPMENT OF DYNAMIC FRACTURE TOUGHNESS TESTING APPARATUS

动态断裂韧性测试仪的研制

基本信息

批准号：
59850019
负责人：
YAGAWA Genki
金额：
$ 12.54万
依托单位：
University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research
财政年份：
1984
资助国家：
日本
起止时间：
1984 至 1986
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-59850019/
关键词：
Dynamic Fracture Test Toughness Fracture Mechanics Visco-plasticity Picture Processing J積分電磁力

项目摘要

In this year, using the dynamic fracture toughness testing system developed so far, the dynamic toughness values of a nuclear pressure vessel steel A508 class 3 were evaluated in a broad temperature range from lower self to upper shelf, and compared with the static values obtained from the three point bending test in literature. It was shown that the dynamic toughness data seemed about 30 to 50% smaller than the static ones, and that the transition temperature shifted by 40 to 50 deg to the higher temperature range. In the upper shelf temperature range, the dynamic toughness data were also a little reduced compared with the static data. The toughness data obtained from the surface force loading test were well coincident with those from the body force ones although the number of surface force loading data was very small. It is expected from the result that the influences of the Joule heating at the vicinity of the crack tip on the fracture toughness data are almost negligible in practic … More e.Also, it seems that the high-strain-rate dependent plasticity as well as inertia forces must be taken into account simultaneously in order to describe accurately the dynamic ductile fracture phenomena. Then we depeloped the finite element analysis program based on an implicit visco-plastic formulation as well as a dynamic and nonlinear fracture mechanics, which was utilized to re-evaluate the dynamic toughness data. The results showed that the dynamic toughness data in upper shelf temperature range increased by about 5% in consideration of strain-rate effects for the fracture parameter calculation. However, the modified dynamic data were still smaller than the static data.The dynamic strain measurement system based on the computer picture processing technique was applied to experimentally evaluate fracture mechanics parameter such as the J-integral. In this method, basing on the deformation theory of plasticity, one calculates the stress distribution for the strain distribution measered by the picture processing technique. Then the J integral can calculated according to the usual path integration scheme. The obtained values of the J-integral had the good path independence and the coincidence with the J integral value from the COD method. The present method can be applied to calculate the J-integral of any shaped two-dimensional cracked specimen since it utilizes the strain-stress data very close a crack tip. Less

在今年，使用到目前为止开发的动态断裂韧性测试系统，核压容器钢A508类3的动态韧性值在从下层到上层架子的广泛温度范围内进行了评估，并将其与文献中从三个点弯曲测试中获得的静态值进行了比较。结果表明，动态韧性数据似乎比静态韧性小约30％至50％，并且过渡温度向更高的温度范围转移了40 dEg。在上货架温度范围内，与静态数据相比，动态韧性数据也有所降低。从表面力载荷测试获得的韧性数据与体力的韧性数据非常吻合，尽管表面力加载数据的数量很小。从结果可以预期的是，裂纹尖端附近的焦耳加热对断裂韧性数据的影响几乎可以忽略不计……而且，似乎更重要的是，似乎必须仅考虑到高应变依赖性的可变性以及惯性力，以便准确地描述动态的致动菌丝菌株。然后，我们基于隐式粘性塑料公式以及动态和非线性断裂力学，对有限元分析程序进行了删除，该计划用于重新评估动态韧性数据。结果表明，考虑到断裂参数计算的应变率效应，上层架子温度范围内的动态韧性数据增加了约5％。但是，修改的动态数据仍然小于静态数据。基于计算机图片处理技术的动态应变测量系统用于实验评估断裂力学参数，例如J构成。在这种方法中，基于可塑性的变形理论，一个人计算出图片处理技术衡量的应变分布的应力分布。然后，J积分可以根据通常的路径集成方案进行计算。 J积分的值获得的值具有良好的路径独立性，并且与COD方法的J积分值相吻合。目前的方法可以应用于计算任何形状的二维开裂样品的J构成，因为它利用应变应力数据非常接近裂纹尖端。较少的