Yoon Soo Park is currently a senior scientist with the Air Force Office of Scientific Research Far East. Prior to his assignment in Japan in September 1983, Dr. Park was a task manager and research physicist at the Avionics Laboratory, Air Force Wright Aeronautical Laboratories. His research interests lie in the areas of electronic materials and devices. Dr. Park is a fellow of the American Physical Society and a senior member of IEEE. Earl F. Skelton is head of the Phase Transformation Section at the Naval Research Laboratory, a professor in the School of Engineering, George Washington University, and a research associate at the University of Hawaii. He has been actively engaged in high pressure research for more than 15 years and spent the past four years developing a facility at Stanford University for ultrarapid structural studies under elevated pressure conditions using synchrotron radiation. Jack L. White is a carbon scientist working in the Materials Sciences Laboratory of the Aerospace Corporation in Los Angeles, California. His current research interests are directed to understanding the properties and mechanisms of formation of such materials as carbon fibers and carbon-fiber-reinforced composites. His experience includes university teaching and consulting to firms in petroleum products development and nuclear power. He has recently been selected by the American Carbon Society as the George D. Graffin Lecturer in Carbon Science and Engineering for 1984. Sachio Yamamoto, a marine chemist, is currently the Director of ONR Far East. He is on leave from his position as head of the Marine Sciences Division at the Naval Ocean Systems Center in San Diego where, since 1969, he has served as a research chemist. Dr. Yamamoto received his Ph.D. in physical chemistry from Iowa State University in 1959, and his research interests are primarily in environmental sciences, trace metal analysis, gas solubility, and x-ray fluorescence analysis. Dr. Yamamoto is a member of the American Chemical Society. Duk Nong Yoon is a professor in the Department of Materials Science and Engineering at the Korea Advanced Institute of Science and Technology (KAIST) in Seoul, Korea. Dr. Yoon received a B.S. degree in physics from the Massachusetts Institute of Technology and a Ph.D. degree in materials science from Harvard University. Dr. Yoon's research interests include powder metallurgy and materials processing. Dr. Yoon has also been visiting scientist at the Max Planck Institute für Metallforschung, West Germany. The Fifth International Congress of Immunology and a International Meetings and Exhibitions 158 160 162 Cover: This woodcut depicts the essence of the Japanese culture which combines the traditional with the modern. The temple, Zojoji, located at Shiba-Koen in Central Tokyo, is juxtaposed against Tokyo Tower which is the tallest man-made structure in Tokyo. This woodblock print is presented here through the courtesy of its artist, Nobuyuki Goto and the Ohfusha Publishing Company which published copies of the artist's prints in a book collection entitled Furusato Yumegeshiki - Shin-Tokyo Hyakkei. ICF INTERNATIONAL SYMPOSIUM ON FRACTURE MECHANICS: Harry I. McHenry INTRODUCTION The ICF International Symposium on Fracture Mechanics was held in Beijing, People's Republic of China, from 22-25 November 1983. The symposium was conducted under the auspices of the International Congress on Fracture (ICF) and was sponsored by the Chinese Society of Theoretical and Applied Mechanics and the Chinese Society of Aeronautics and Astronautics. The symposium agenda started with registration and a visit to the Beijing Institute of Aeronautics and Astronautics on Monday, 21 November. The technical sessions started on Tuesday with a full day of invited lectures, 16 lectures in two parallel sessions. On Wednesday and Thursday, 102 contributed papers were presented in four parallel sessions. The attendance was 158 scientists, including 114 Chinese and 44 delegates from ten other countries. The 44 foreign participants included 12 from the U.S.A., 15 from Japan, and 16 from Europe. The proceedings of the symposium, consisting of 132 papers, were published and distributed during registration. A review of the proceedings indicates that the papers fall in three general categories: theoretical and analytical fracture mechanics (42 papers, 30 from China), - subcritical crack growth (46 papers, 19 from China). In this report, the technical papers are discussed under these three headings. The key issues are identified with emphasis on the invited papers and the papers from China. The tour of the Beijing Institute of Aeronautics and Astronautics is briefly described. THEORETICAL AND ANALYTICAL FRACTURE MECHANICS The Office of Naval Research was well represented with two of the four invited lectures in this topical area covering ONR-sponsored research. Professor S. N. Atluri of the Georgia Institute of Technology presented, "Computational and Theoretical Studies on Dynamic Fracture Mechanics and Three-dimensional Crack Problems." This paper summarized recent work that has been previously published (1980-1983) in 21 papers by this remarkably productive researcher and his coinvestigator, Dr. T. Nishioka. A moving singular element procedure is described for elastodynamic problems of fast crack propagation in finite bodies. The accuracy of the analysis was verified by comparing the results with analytic solutions for infinite domain cases. The method was used to study the fast fracture behavior of dynamic tear (DT) test specimens of 4340 steel, and used as the basis for proposing a method for determining dynamic stress intensity factors directly from crack mouth opening displacements in a DT test. Path independent integrals were derived to characterize the severity of the stress field at the tip of an elastodynamically propagating crack. Professor Atluri's paper also describes research on three-dimensional crack problems. The alternating method of Shah and Kobayashi (Engr. Fract. Mech., 1971) has been extended by deriving a complete general analytical solution for an elliptical crack embedded in an infinite elastic medium and subject to arbitrary tractions. The new alternating method is used in conjuction with finite element analysis to enable the rapid (with respect to computer time) and accurate calculation of stress intensity factors for flaws in structures. The method has been used to solve a variety of problems including corner cracks, surface flaws and embedded flaws in finite-thickness plates, bars, and lugs. The other invited lecture covering ONR-sponsored research was a paper entitled, "Plastic Deformation and Hardening Characteristics in Three-dimensional Fracture Specimens," by E. T. Moyer, Jr. and H. Liebowitz. In the paper, the finite element formulation for general 3-D elastic bodies is presented for the case of small strain plasticity. The finite element analysis program based on this formulation is used to compute the crack tip yield contours for hardening models: isotropic, kinematic, and mixed. The von Mises yield criterion was used in all three models. The size and shape of the plastic zones calculated by each hardening model were similar. No conclusions were drawn. The oral presentation was a tutorial on how to develop a code for a VAX-type computer based on the formulation presented in the paper. Not being competent in that area, I found it dreadful, but the Chinese members of the audience were all ears, and there were numerous detailed questions following the presentation. In the area of fracture theory, several ideas that were new to this fracture mechanics audience were introduced in a lively session in which Dr. I. H. Lin of the National Bureau of Standards (NBS) presented his paper, "Dislocation-shielding Analysis of a Blunt-notched Brittle Crack Embedded in a Ductile Material" and a paper by his NBS colleague, Dr. R. M. Thomson entitled, "Dislocation Shielding of Cracks and the Fracture Criterion." Dr. Lin was given 40 minutes for the "double-paper" and it was followed by 40 minutes of vigorous discussion in the best traditions of a technical meeting. Three ideas were presented that had been introduced in previous papers but are quite new. First, an elastic enclave exists between exists between the crack tip and the plastic zone (Thomson, J. Matls. Sci, 1978, and Weertman Acta Met, 1978); dislocations that would be in this zone are either repelled into the plastic zone or absorbed by the crack tip. Second, the crack tip is shielded by dislocations which reduce the local crack-tip stress intensity below that computed based on continuum theory (Majumdai and Burns, Acta Met, 1981, Thomson and Sinclair, Acta Met, 1982), i.e., the dislocations surrounding the crack tip exert a closure force on the crack. Third, dislocations are emitted from the crack (Rice and Thomson, Phil. Mag., 1974) and emission continues until the resulting dislocation pileup reduces the local stress intensity below that required for emission (Lin and Thomson, Scripta Met, 1983). Similar topics were discussed in a presentation by Professor J.C.M. Li of the University of Rochester entitled, "Dynamic Emission of Dislocations from a Crack Tip: A Computer Simulation,' by R. H. Zhao, S. H. Dai, and J.C.M. Li. The ideas of dislocation emission, dislocation shielding, and elastic enclave offer insight into experimental observations that are not consistent with continuum theory, e.g., an atomically sharp crack and the existence of a dislocation free zone at the crack tip. It was a pleasure to hear them expressed to a fracture mechanics audience. We are likely to hear more about them at future meetings. Of the 42 papers on theory and analysis, 30 were by Chinese authors. One of these papers was an invited presentation by Hwang Keh-chih and Liu Chuntu entitled, "Some Theoretical Works on Fracture Mechanics in China." This paper was limited to analytical studies at the Institute of Mechanics, Qinghua (Tsinghua) University, and the Harbin Shipbuilding Engineering Institute. The paper reviewed 41 previously published papers including some that were published originally in Chinese and then again at this conference. Emphasis was on the works of He Ming-yuan (six papers) who studied at |