In this book the authors focus on the description of the physical nature of cleavage fracture to offer scientists, engineers and students a comprehensive physical model which vividly describes the cleavage microcracking processes operating on the local (microscopic) scale ahead of a defect. The descriptions of the critical event and the criteria for cleavage fracture will instruct readers in how to control the cleavage processes and optimize microstructure to improve fracture toughness of metallic materials. Physical (mechanical) processes of cleavage fracture operating on the local (microscopic) scale, with the focus on the crack nucleation and crack propagation across the particle/grain and grain/grain boundaries Critical event, i.e., the stage of greatest difficulty in forming the microcrack, which controls the cleavage fracture Criteria triggering the cleavage microcracking with incorporation of the actions of macroscopic loading environment into the physical model Effects of microstructure on the cleavage fracture, including the effects of grain size, second phase particles and boundary Comprehensive description of the brittle fracture emerging in TiAl alloys and TiNi memory alloys
|Author||: Heikki Kotilainen|
|Release Date||: 1980|
|Pages||: 133 pages|
Fracture and Fatigue: Elasto-Plasticity, Thin Sheet and Micromechanisms Problems covers the proceedings of the Third Colloquium on Fracture. The book discusses the development and applications of fracture mechanics. The contents of the text are organized according to the areas of concerns. The first part deals with elasto-plastic fracture mechanics, which includes topics such as fracture mechanics in the elastic-plastic regime and sizing of the geometry dependence and significance of maximum load toughness values. Part II covers the micromechanisms of fracture, which includes the aspects of crack growth under monotonic loading and the effect of secondary hardening on the fracture toughness of a bainitic microstructure. Part III concerns itself with thin sheet fracture mechanics, which includes R-curves evaluation for center-cracked panels and use of the R-curve for design with contained yield. The book will be of great interest to researchers and professionals whose work involves fracture mechanics.
The main scope of this Cargese NATO Advanced Study Institute (June 5-17 2000) was to bring together a number of international experts, covering a large spectrum of the various Physical Aspects of Fracture. As a matter of fact, lecturers as well as participants were coming from various scientific communities: mechanics, physics, materials science, with the common objective of progressing towards a multi-scale description of fracture. This volume includes papers on most materials of practical interest: from concrete to ceramics through metallic alloys, glasses, polymers and composite materials. The classical fields of damage and fracture mechanisms are addressed (critical and sub-critical quasi-static crack propagation, stress corrosion, fatigue, fatigue-corrosion . . . . as well as dynamic fracture). Brittle and ductile fractures are considered and a balance has been carefully kept between experiments, simulations and theoretical models, and between the contributions of the various communities. New topics in damage and fracture mechanics - the effect of disorder and statistical aspects, dynamic fracture, friction and fracture of interfaces - were also explored. This large overview on the Physical Aspects of Fracture shows that the old barriers built between the different scales will soon "fracture". It is no more unrealistic to imagine that a crack initiated through a molecular dynamics description could be propagated at the grain level thanks to dislocation dynamics included in a crystal plasticity model, itself implemented in a finite element code. Linking what happens at the atomic scale to fracture of structures as large as a dam is the new emerging challenge.
Over recent years there has been a tremendous upsurge in interest in the fracture behaviour of polymers. One reason for this is the increas ing use of polymers in structural engineering applications, since in such circumstances it is essential to have as complete an understanding as possible of the polymer's fracture behaviour. This book is designed to meet the requirements of those who need to be informed of the latest developments in the field of polymer fracture. It is written particularly for research workers but it should also prove invaluable for advanced students taking final-year undergraduate or postgraduate courses. The main emphasis is upon the use of fracture mechanics in the study of polymer fracture but this approach is then developed to cover the micromechanisms of the fracture process. Particular prominence is given to the relationship between structure, mechanical properties and the mechanics and mechanisms of fracture. The first chapter is a brief introduction which has several aims. One is to introduce polymers to the reader who does not have a strong background in the subject and another is to provide background material that will be used at later stages. The book is then split into two main parts: the first deals with the mechanics and mechanisms whilst the second is concerned with materials. In Part I phenomena such as molecular fracture, fracture mechanics, shear yielding and crazing are covered from a general viewpoint.
|Author||: P. B. Hirsch|
|Publisher||: CRC Press|
|Release Date||: 2019-11-11|
|ISBN 10||: 1000716988|
|Pages||: 212 pages|
This volume brings together the papers presented at the 7th Symposium organised by the Technical Advisory Group on Structural Integrity of Nuclear Plant (TAGS!) which was held at the TWI Conference Centre, Great Abington, UK on 29 April 1999. The Symposium, which marked 25 years of TAGSI and its predecessor, the Light Water Reactor Study Group (LWRSG), was dedicated to Sir Alan Cottrell FREng, FRS, whose impact on the fields of integrity, reliability and safety of engineering structures and components has been second to none.
|Author||: Harold Liebowitz|
|Release Date||: 1969|
|Pages||: 329 pages|
As Directors of this NATO Workshop, we welcome this opportunity to record formally our thanks to the NATO Scientific Affairs Division for making our meeting possible through generous financial support and encouragement. This meeting has two purposes: the first obvious one because we have collected scientists from East, far East and west to discuss new development in the field of fracture mechanics: the notch fracture mechanics. The second is less obvious but perhaps in longer term more important that is the building of bridges between scientists in the frame of a network called Without Walls Institute on Notch Effects in Fatigue and Fracture". Physical perception of notch effects is not so easy to understand as the presence of a geometrical discontinuity as a worst effect than the simple reduction of cross section. Notch effects in fatigue and fracture is characterised by the following fundamental fact: it is not the maximum local stress or stress which governs the phenomena of fatigue and fracture. The physic shows that a process volume is needed probably to store the necessary energy for starting and propagating the phenomenon. This is a rupture of the traditional "strength of material" school which always give the prior importance of the local maximum stress. This concept of process volume was strongly affirmed during this workshop.