This book demonstrates fatigue crack growth under random loading graphically. This state-of-the-art monograph introduces an expert system for crack growth predictions, particularly based on crack closure. The system is developed after years of research by the authors by using the Math-type software consisting of 5 parts. This system is unique as it is fundamentally different from previous systems as it focuses on fatigue crack growth predictions based on fatigue crack closure. This book can be a useful guide for practicing engineers, researchers, and students in the fields of mechanical, aerospace, or civil engineering.

Author Biography:Jiho Song is Professor Emeritus of Mechanical Engineering at Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea. He received his B.S. (1969), M.S. (1971) and Dr. Engineering (1974) in Mechanical Engineering at Osaka University, Osaka, Japan, under the guidance of Professor Makoto Kikukawa. In 1975, he was Wissenschaftlicher Mitarbeiter in Lehrstuhl Mechanik A at Technische Universit�t M�nchen, Munich, Germany, with the help of Professor Klaus Heckel. In 1977 He joined Hanyang University, Seoul, Korea and then moved to Osaka University, Japan, in 1982 as a Research Associate with the support of Professor Masahiro Jono. He returned to Korea in 1985 as a Professor at KAIST, becoming Professor Emeritus in 2011. He taught courses in fatigue, strength design, reliability engineering, and design engineering. He received four times departmental outstanding teaching awards. His principal field of research is fatigue and fatigue-related database and expert system. He published several books: Fatigue Cracks-Crack Closure and Growth Rate Prediction, (in Japanese) in 2005 with Professor Masahiro Jono, (in Korean) in 2006. Introduction to Reliability Engineering, (in Korean) in 2007. Dictionary of Fatigue Fracture and Fatigue Strength of Materials (FatiguePedia of Materials), (in Korean) in 2011. Fundamentals of Fatigue Analysis, (in Korean) in 2016.Book Description:Fatigue of materials is very important in designing mechanical structures and components. Recently, fatigue databases, databanks and some computer software have been developed for fatigue analysis or fatigue life predictions, and some of them have been commercially available. Those fatigue databases and fatigue analysis software tools are clearly very helpful for the design and analysis engineers to select materials, analyze fatigue performance or estimate fatigue life of structures and components. In order to utilize those databases and software tools successfully in practice, engineers as users are implicitly required to have, more or less, wide and deep, and sometimes even advanced knowledge of fatigue; in other words, this book conveys considerable expertise in fatigue. However, most of the design and analysis engineers do not always have sufficient knowledge in fatigue and therefore, it is not yet easy for them to conduct fatigue design and analysis successfully, although there are many databases and software tools available.An expert system is a very useful, convenient and powerful tool for ordinary engineers to treat complicated engineering problems such as fatigue design and analysis, which require considerable expertise. Although the importance of fatigue expert systems has long been recognized, there is hardly any practically available fatigue expert system to date.Over many years, the authors have been developing some expert systems for fatigue assessment, particularly for the estimation of fatigue properties and for fatigue crack initiation life prediction under variable loading. Recently, in response to a scientific research result, the authors have developed a practically applicable version. They think that the expert system developed is probably the first and only fatigue expert system in the world.This book introduces in detail the expert systems developed and provides the expert system software, most probably in CD. Although it is not developed for commercial purposes, the system software is very easy to use.This book and the fatigue expert system software may be useful for nearly all engineers, researchers and technologists from the academic, industrial and government sectors who engage in engineering design and the maintenance of structures. This book is also designed for advanced undergraduate and beginning graduate-level engineering students in universities, particularly in the department of mechanical engineering, aerospace engineering, civil engineering and metallurgy.Target Audience:Nearly all engineers, researchers and technologists from the academic, industrial and government sectors who engage in engineering design and maintenance of structures.Advanced undergraduate and beginning graduate-level engineering students in universities, particularly in the department of mechanical engineering, aerospace engineering, civil engineering, and metallurgy.

This book offers a concise introduction to fatigue crack growth, based on practical examples. It discusses the essential concepts of fracture mechanics, fatigue crack growth under constant and variable amplitude loading and the determination of the fracture-mechanical material parameters. The book also introduces the analytical and numerical simulation of fatigue crack growth as well as crack initiation. It concludes with a detailed description of several practical case studies and some exercises. The target group includes graduate students, researchers at universities and practicing engineers.

A ligament model, which performs a simplified, one-dimensional elastic-plastic analysis to predict fatigue crack closure behavior, is described. The model is a modification and extension of a similar one developed by Newman and has the ability to predict the influence of pre-existing residual stress fields on crack closure. Different aspects of the model are examined and, where possible, compared with experimental data and with results from theoretical studies in the literature. For specimens without pre-existing residual stresses, the aspects examined include prediction of plasticity and closure induced residual stresses near the crack tip and prediction of the influence of applied mean stress on crack opening stress. For specimens with pre-existing residual stresses, aspects examined include prediction of residual stress redistribution caused by crack growth and prediction of the influence of such stresses on crack growth behavior, using the closure concept of an effective stress intensity range. Predictions of crack growth are also compared to those based on the superposition approach, for both compressive and tensile residual stresses.