In this second edition, which is the result of numerous revisions, updates and additions, the authors cover the basic concepts of fracture mechanics for both the linear elastic and elastic-plastic regimes. The fracture mechanics parameters K, G, J and CTOD are treated in a basic manner along with the test methods to determine critical values. The development of failure assessment based on elastic-plastic fracture mechanics is reflected in a comprehensive treatment. Three chapters are devoted to the fracture mechanics characterisation of crack growth. Fatigue crack growth is extensively treated and attention is paid to the important topic of the initiation and growth of short fatigue cracks. Furthermore, sustained load fracture and dynamic crack growth are discussed, including various test techniques, e.g. the determination of the crack arrest toughness. Finally, there are two chapters dealing with mechanisms of fracture and the ways in which actual material behaviour influences the fracture mechanics characterisation of crack growth. This textbook is intended primarily for engineering students. It will be useful to practising engineers as well, since it provides the background to several test and design methods and to criteria for material selection.@en

The fracture toughness of high strength steels is commonly determined by standard methods using Compact tension (CT) or Single edge notched bend (SENB) specimens. In the past the Circumferentially Notched Tension (CNT) geometry has been reported as a potential candidate for determining the fracture toughness of highly constrained cracks, theoretically approaching plane strain conditions, even for small specimen dimensions. The goal of this study is to develop a more fundamental understanding of the CNT methodology and apply it to high strength S690QT steel. An alternative prefatiguing method was developed and a straightforward relation was established between the Crack Mouth Opening Displacement (CMOD) and the Crack Tip Opening Displacement (CTOD). With the new experimental aspects, it proved feasible to determine upper-shelf CTOD values for S690QT steel, using small CNT specimens (D = 12 mm), tested at room temperature with a relative high loading rate. Furthermore, CNT low temperature values were found comparable to those of conventional SENB tests. Hence, the research demonstrates that CNT geometry allows for small scale high loading rate specimen testing, resulting in simple, rapid and cost effective fracture toughness determination.@en