Defects Fracture And Fatigue

The Second International Symposium on Defects, Fracture and Fatigue took place at Mont Gabriel, Quebec, Canada, May 30 to June 5, 1982, and was organized by the Mechanical Engineering Department of McGill University and Institute of Fracture and Solid Mechanics, Lehigh University. The Co-Chairmen of the Sympo sium were Professor G.C. Sih of Lehigh University and Professor J.W. Provan of McGill University. Among those who served on the Organizing Committee were G.C. Sih (Co-Chairman), J.W. Provan (Co-Chairman), H. Mughrabi, H. Zorski, R. Bullough, M. Matczynski, G. Barenblatt and G. Caglioti. As a result of the interest expressed at the First Symposium that was held in October 1980, in Po land, the need for a follow-up meeting to further explore the phenomena of mate rial damage became apparent. Among the areas considered were dislocations, per sistent-slip-bands, void creation, microcracking, microstructure effects, micro/ macro fracture mechanics, ductile fracture criteria, fatigue crack initiation and propagation, stress and failure analysis, deterministic and statistical crack models, and fracture control. This wide spectrum of topics attracted researchers and engineers in solid state physics, continuum mechanics, applied mathematics, metallurgy and fracture mechanics from many different countries. This spectrum is also indicative of the interdisciplinary character of material damage that must be addressed at the atomic, microscopic and macroscopic scale level.

On Fracture Mechanics A major objective of engineering design is the determination of the geometry and dimensions of machine or structural elements and the selection of material in such a way that the elements perform their operating function in an efficient, safe and economic manner. For this reason the results of stress analysis are coupled with an appropriate failure criterion. Traditional failure criteria based on maximum stress, strain or energy density cannot adequately explain many structural failures that occurred at stress levels considerably lower than the ultimate strength of the material. On the other hand, experiments performed by Griffith in 1921 on glass fibers led to the conclusion that the strength of real materials is much smaller, typically by two orders of magnitude, than the theoretical strength. The discipline of fracture mechanics has been created in an effort to explain these phenomena. It is based on the realistic assumption that all materials contain crack-like defects from which failure initiates. Defects can exist in a material due to its composition, as second-phase particles, debonds in composites, etc. , they can be introduced into a structure during fabrication, as welds, or can be created during the service life of a component like fatigue, environment-assisted or creep cracks. Fracture mechanics studies the loading-bearing capacity of structures in the presence of initial defects. A dominant crack is usually assumed to exist.

Fracture, fatigue, and other subcritical processes, such as creep crack growth or stress corrosion cracking, present numerous open issues from both scientific and industrial points of view. These phenomena are of special interest in industrial and civil metallic structures, such as pipes, vessels, machinery, aircrafts, ship hulls, and bridges, given that their failure may imply catastrophic consequences for human life, the natural environment, and/or the economy. Moreover, an adequate management of their operational life, defining suitable inspection periods, repairs, or replacements, requires their safety or unsafety conditions to be defined. The analysis of these technological challenges requires accurate comprehensive assessment tools based on solid theoretical foundations as well as structural integrity assessment standards or procedures incorporating such tools into industrial practice. This volume is focused on new advances in fracture, fatigue, and structural integrity of metallic structural components containing defects (e.g., cracks, notches, metal loss, etc.), and also on those developments that are being or could be incorporated into structural integrity assessment procedures, such as BS7910, R6, or API 579-1/ASME FFS-1.

The Welding Engineer's Guide to Fracture and Fatigue provides an essential introduction to fracture and fatigue and the assessment of these failure modes, through to the level of knowledge that would be expected of a qualified welding engineer. Part one covers the basic principles of weld fracture and fatigue. It begins with a review of the design of engineered structures, provides descriptions of typical welding defects and how these defects behave in structures undergoing static and cyclical loading, and explains the range of failure modes. Part two then explains how to detect and assess defects using fitness for service assessment procedures. Throughout, the book assumes no prior knowledge and explains concepts from first principles. Covers the basic principles of weld fracture and fatigue. Reviews the design of engineered structures, provides descriptions of typical welding defects and how these defects behave in structures undergoing static and cyclical loading, and explains the range of failure modes. Explains how to detect and assess defects using fitness for service assessment procedures.

Metal fatigue is an essential consideration for engineers and researchers looking at factors that cause metals to fail through stress, corrosion, or other processes. Predicting the influence of small defects and non-metallic inclusions on fatigue with any degree of accuracy is a particularly complex part of this. Metal Fatigue: Effects of Small Defects and Nonmetallic Inclusions is the most trusted, detailed and comprehensive guide to this subject available. This expanded second edition introduces highly important emerging topics on metal fatigue, pointing the way for further research and innovation. The methodology is based on important and reliable results and may be usefully applied to other fatigue problems not directly treated in this book. Demonstrates how to solve a wide range of specialized metal fatigue problems relating to small defects and non-metallic inclusions. Provides a detailed introduction to fatigue mechanisms and stress concentration. This edition is expanded to address even more topics, including low cycle fatigue, quality control of fatigue components, and more.

Fatigue and fracture result in billions of dollars of damage each year. This book examines the various causes of fatigue including crack growth, defects, temperature, environmental, and corrosion.