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

The principal purpose of this project is to investigate the elastic-plastic crack-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 held10times during#china_person0#-1990 to discuss experimental and numerical works.Six researchers(G.Yagawa，S.Yoshimura，H.Homma，S.Aoki，M.Nakagaki and N.Miyaki)have visited USA eight times to perform cooperative works and to investigate the state-of-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，#china_person0#and in the end of June，1990 to perform a cooperative work on numerical analyses on elastic-plastic crack growth in inhomogeneous materials.H.Homma visited SRI international and the University of Maryland for one month in#china_person1#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 emes elelic for plastic craste.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#china_person0#)，in California(10th SMiRT Conf.，Aug.of#china_person1#)，in Atlanta(ASTM STP Conf.，June of 1990)，in Boston(Aug.1990)，and in Washington D.C.(Oct.1990)。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-plastic fracture phenomena of inhomogeneous materials and structures have been surveyed through ject his.Less：Less

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