Study on Elastic ー Plastic Fracture Machanics in Nonhomogeneous Materials and Structures

该项目的主要目标是研究弹性-塑料裂纹-在非同源材料和结构中生长现象，在日本和美国研究财团之间合作工作中发展一些碎片抵抗估计方案的过程中。1989-1990年期间，国家会议已完成10次，以讨论实验和数字工作。Six researchers （G. Yagawa， S. Yoshimura， H. Homma， S. Aoki， M。Nakagaki and N. Miyazaki）曾访问过美国八次执行合作作品，并对该领域的艺术进行调查。首先，这个项目的活动可以按以下方式总结：S.吉村访问了格鲁吉亚技术研究所， 1989年7月中旬和1990年6月下旬，以完成关于弹性-非同源材料中塑料裂纹增长的数字分析的合作工作。1989年夏天访问SRI国际和马里兰大学一个月的校园 ... More 关于动态裂纹传播实验的强制性工作在各种热力条件下进行的数值和实验研究。在橡树岭国家实验室进行了实验。长崎访问了乔治亚理工学院，从7月中旬到8月结束。1990年，在非同源材料中执行Crack Growth Simulation的合作工作。Miyazaki访问了Battelle Columbus实验室，从11月中旬到12月的尽头。1990年将在弹性-塑料裂纹生长阻力的2D和3D简单估计方案上执行合作工作。在这些时期，日本研究人员（G.）Yagawa等人）美国研究人员（美国核研究中心、橡树岭国家实验室）Battelle Columbus实验室和乔治亚理工学院在讨论夏威夷的任务和时间表，并对研究结果进行了多次讨论（ASME PVP会议，1989年7月，加利福尼亚州（第10届SMiRT会议）1989年8月），亚特兰大（ASTM STP会议，1990年6月），在波士顿（1990年8月），在华盛顿特区。C. C.（1990年10月）.该项目的结果可以概括为：（1）通过日本和美国关于弹性实验和数字实验之间的研究共识-不同源基因物种中的塑料裂纹生长，发现了一个传统的J-Integral可以描述不同源基因物种中裂纹生长的定量行为。（2）使用加载历史和压力与紧张关系的常规简单估计方案需要对材料属性的选择进行特定修改。（3）各种弹性-塑料碎片现象的不同源材料和结构已经通过本项目进行了调查。Less（低）

The principal purpose of this project is to investigate the elasticーplastic crackーgrowth phenomena in inhomogeneous materials and structures, aming at the development of some estimation schemes of fracture resistance through the cooperative work between Japanese and US research consortia.The national meetings have been held 10 times during 1989-1990 to discuss experimental and numerical works. Six researchers (G. Yagawa, S. Yoshimura, H. Homma, S. Aoki, M. Nakagaki and N. Miyazaki) have visited USA eight times to perform cooperative works and to investigate the stateーofーthe art of the field. First, the activities of this project can be summarized as follows :S. Yoshimura visited Georgia Institute of Technology in the middle of July, 1989 and in the end of June, 1990 to perform a cooperative work on numerical analyses on elasticーplastic crack growth in inhomogeneous materials.H. Homma visited SRI international and the University of Maryland for one month in 1989 summer to perform a coop … More erative work on numerical and experimental studies on dynamic crack propagation experiments under anisothermal conditions. The fracture experiments was performed in Oak Ridge National Laboratory.M. Nakagaki visited Georgia Institute of Technology from the middle of July to the end of Aug., 1990 to perform a cooperative work on crack growth simulation in inhomogeneous materials.N. Miyazaki visited Battelle Columbus Laboratory from the middle of Nov. to the end of Dec., 1990 to perform a cooperative work on 2D and 3D simple estimation schemes for elasticーplastic crack growth resistance.During these periods, Japanese researchers (G. Yagawa et al.) and US reseachers (USNRC, Oak Ridge National Lab., Battelle Columbus Lab. and Georgia Institute of Technology) have had several meetings to discuss the tasks and time schedule and to review research results in Hawaii (ASME PVP Conf., July of 1989), in California (10th SMiRT Conf., Aug. of 1989), in Atlanta (ASTM STP Conf., June of 1990), in Boston (Aug. 1990), and in Washington D. C. (Oct. 1990).The results of this project can be summarized as follows :(1) Through the cooperative and systematic experimental and numerical works between Japanese and US research consortia on elasticーplastic crack growth in inhomogeneous specimens, it is found that the conventional J-integral can describe quantitative behaviors of crack growth even in inhomogeneous specimens.(2) The conventional simple estimation schemes which use loading history and a stress vs. strain relationship require a certain modification on choice of material properties.(3) Various elasticーplastic fracture phenomena of inhomogeneous materials and structures have been surveyed through this project. Less