Current Research on Fatigue Cracks (in English)

Abstract

In recent years Japanese researchers have been active in studies of crack growth behavior, but the findings have often been presented only in the Japanese language. This publication in English is intended to present the important recent results of selected works of some of the leading Japanese researchers in an effort to promote wider dissemination of these findings and thereby contribute to worldwide progress in science and technology. It is well to be aware of these contributions which are distinguished by insight, exactitude in experimental work, and novel experimental procedures. However the editors are a bit modest, for in fact many of the authors of the papers in this volume are highly respected outside of Japan for their contributions to research. Three topics are treated, namely, short fatigue cracks, fatigue crack growth and the threshold, and corrosion fatigue ''cracks. H. Nisitani discusses the behavior of small cracks and related phenomena, K. Yamada, M. Shimizu, and T. Kunio treat the threshold behavior of small cracks, M. Jono and J. Song write on the growth and closure of short cracks, K. Ogura, Y. Miyoshi and I. Nishikawa discuss small cracks at notch roots, K. Tanaka describes short crack fracture mechanics, and S. Usami discusses short cracks and component life estimation. A. Otsuka, K. Mori, and K. Tohgo write on Mode II fatigue crack growth in aluminum alloys, A. Ohta, E. Sasaki, M. Kosuge and S. Nishijima discuss the threshold for welded joints, K. Asami deals with fatigue crack growth in high strength steel, H. Kobayashi and H. Nakamura analyze plasticity induced closure, and M. Kurihara, A. Katoh and M. Kawahara discuss the effects of stress ratio and step loading on the rate of fatigue crack growth.

Growth of Short Fatigue Cracks Emanating from Notches in an Austenitic-Ferritic Stainless Steel

“…Studies of the short fatigue cracks emanating from stress concentrations [1,2] reveal that, compared to fracture mechanics predictions, small cracks grow at higher rates and bellow the long crack threshold. Depending on the stress level such fast growing cracks eventually slow-down or arrest as the crack front leaves the notch plastic zone and the stress and strain diminish.…”