Nonlinear Fracture Mechanics Time Dependent Fracture

Intended for engineers, researchers, and graduate students dealing with materials science, structural design, and nondestructive testing and evaluation, this book represents a continuation of the author's "Fracture Mechanics" (1997). It will appeal to a variety of audiences: The discussion of design codes and procedures will be of use to practicing engineers, particularly in the nuclear, aerospace, and pipeline industries; the extensive bibliography and discussion of recent results will make it a useful reference for academic researchers; and graduate students will find the clear explanations and worked examples useful for learning the field. The book begins with a general treatment of fracture mechanics in terms of material properties and loading and provides up-to-date reviews of the ductile-brittle transition in steels and of methods for analyzing the risk of fracture. It then discusses the dynamics of fracture and creep in homogeneous and isotropic media, including discussions of high-loading-rate characteristics, the behavior of stationary cracks in elastic media under stress, and the propagation of cracks in elastic media. This is followed by an analysis of creep and crack initiation and propagation, describing, for example, the morphology and incubation times of crack initiation and growth and the effects of high temperatures. The book concludes with treatments of cycling deformation and fatigue, creep-fatigue fractures, and crack initiation and propagation. Problems at the end of each chapter serve to reinforce and test the student's knowledge and to extend some of the discussions in the text. Solutions to half of the problems are provided.

Fracture mechanics is an essential tool for engineers in a number of different engineering disciplines. For example, an engineer in a metals- or plastics-dependent industry might use fracture mechanics to evaluate and characterize materials, while another in aerospace or construction might use fracture mechanics-based methods for product design and service life-time estimation. This balanced treatment, which covers both applied engineering and mathematical aspects of the topic, provides a much-needed multidisciplinary treatment of the field suitable for the many diverse applications of the subject. While texts on linear elastic fracture mechanics abound, no complete treatments of the complex topic of nonlinear fracture mechanics have been available in a textbook format - until now. Written by an author with extensive industry credentials as well as academic experience, Nonlinear Fracture Mechanics for Engineers examines nonlinear fracture mechanics and its applications in mechanics, materials testing, and life prediction of components. The book includes the first-ever complete examination of creep and creep-fatigue crack growth. Examples and problems reinforce the concepts presented. A complete chapter on applications and case studies involving nonlinear fracture mechanics completes this thorough evaluation of this dynamic field of study.

From time to time the International Journal of Fracture has presented special matters thought to be of interest to its readers. In previous issues, for example, Dr. H.W. Liu as Guest Editor assembled a series of review papers dealing with fatigue processes and characteristics in metals and non-metals (December 1980 and April 1981). Five years ago Guest Editor W.G. Knauss collected works dealing with dynamic fracture (March and April 1985). Continuing this policy, Dr. W.G. Knauss and Dr. A.J. Rosakis of the California Institute of Technology as Guest Editors have now organized an extensive set of papers concerning the influence of non-linear effects upon the mechanics of the fracture process. This collection is based upon contributions to a relatively small international Symposium on Non Linear Fracture Mechanics held under the auspices of the International Union of Theoretical and Applied Mechanics (IUTAM) and convened at the California Institute of Technology in March 1988. It should be noted that although the description of non-linear fracture inherently encompasses a strong material science component, this aspect is not heavily emphasized in the ensuing papers due to the intentional focus upon mechanics. Volume 42 of the International Journal of Fracture will therefore, in successive issues, deal respectively with topics in (1) Damage, (2) Interfaces and Creep, (3) Time Dependence, and (4) Continuum Plasticity. On behalf of the editors and publishers, I wish to express our appreciation to Dr. Knauss, Dr. Rosakis, and their colleagues for their collective efforts.

The understanding of time dependent crack propagation processes occupies a central place in the study of fracture. It also encompasses a wide range of conditions: failure under sustained loading in a corrosive environment, fracture under cyclic loading in non-degrading and in corrosive environment, and rupture at high temperature. This list covers probably 90% of the failures that occur in engineering practice. The process of time dependent fracture is controlled by the physics of atomic interaction changes; it is strongly influenced by the micro structure; and affected by the interaction of the material with the mechanical (load, displacement), the thermal (temperature), and the chemical or radiation environment. To be able to control crack propagation the development of testing methods and the understanding of the industrial environment is essential. The conference was organized in this context. A call was issued for contributions to the following topics. THERMAL ACTIVATION. Theoretical papers dealing with the modification of fracture mechanics to accommodate thermally activated processes. TIME DEPENDENT MICRO-PROCESSES. Presentations covering both the theoretical and observational aspects of creep and fatigue damage in materials whose microstructures may exert a significant influence on crack growth. INDUSTRIAL APPLICATIONS. Submissions describing the practical application of fracture mechanics and damage tolerance analysis to the determination of useful operating lives. x ENVIRONMENTAL EFFECTS. Papers dealing with engineering materials and/or components exposed to aggressive environments, with and without temperature effects. The response was gratifying. Leading experts responded; the organizers of the conference are grateful for the large number of excellent contributions.