Mechanics of Fracture Initiation and Propagation

Mechanics of Fracture Initiation and Propagation PDF Author: George C. Sih
Publisher: Springer Science & Business Media
ISBN: 940113734X
Category : Science
Languages : en
Pages : 429

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Book Description
The assessment of crack initiation and/or propagation has been the subject of many past discussions on fracture mechanics. Depending on how the chosen failure criterion is combined with the solution of a particular theory of continuum mechanics, the outcome could vary over a wide range. Mod elling of the material damage process could be elusive if the scale level of observation is left undefined. The specification of physical dimension alone is not sufficient because time and temperature also play an intimate role. It is only when the latter two variables are fixed that failure predictions can be simplified. The sudden fracture of material with a pre-existing crack is a case in point. Barring changes in the local temperature,* the energy released to create a unit surface area of an existing crack can be obtained by considering the change in elastic energy of the system before and after crack extension. Such a quantity has been referred to as the critical energy release rate, G e, or stress intensity factor, K Ie. Other parameters, such as the crack opening displacement (COD), path-independent J-integral, etc. , have been proposed; their relation to the fracture process is also based on the energy release concept. These one-parameter approaches, however, are unable simultaneously to account for the failure process of crack initiation, propagation and onset of rapid fracture. A review on the use of G, K I, COD, J, etc. , has been made by Sih [1,2].

Mechanics of Fracture Initiation and Propagation

Mechanics of Fracture Initiation and Propagation PDF Author: George C. Sih
Publisher: Springer Science & Business Media
ISBN: 940113734X
Category : Science
Languages : en
Pages : 429

Get Book Here

Book Description
The assessment of crack initiation and/or propagation has been the subject of many past discussions on fracture mechanics. Depending on how the chosen failure criterion is combined with the solution of a particular theory of continuum mechanics, the outcome could vary over a wide range. Mod elling of the material damage process could be elusive if the scale level of observation is left undefined. The specification of physical dimension alone is not sufficient because time and temperature also play an intimate role. It is only when the latter two variables are fixed that failure predictions can be simplified. The sudden fracture of material with a pre-existing crack is a case in point. Barring changes in the local temperature,* the energy released to create a unit surface area of an existing crack can be obtained by considering the change in elastic energy of the system before and after crack extension. Such a quantity has been referred to as the critical energy release rate, G e, or stress intensity factor, K Ie. Other parameters, such as the crack opening displacement (COD), path-independent J-integral, etc. , have been proposed; their relation to the fracture process is also based on the energy release concept. These one-parameter approaches, however, are unable simultaneously to account for the failure process of crack initiation, propagation and onset of rapid fracture. A review on the use of G, K I, COD, J, etc. , has been made by Sih [1,2].

Mechanics of Fracture Initiation and Propagation

Mechanics of Fracture Initiation and Propagation PDF Author: George C. Sih
Publisher: Springer
ISBN:
Category : Science
Languages : en
Pages : 440

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Book Description
The assessment of crack initiation and/or propagation has been the subject of many past discussions on fracture mechanics. Depending on how the chosen failure criterion is combined with the solution of a particular theory of continuum mechanics, the outcome could vary over a wide range. Mod elling of the material damage process could be elusive if the scale level of observation is left undefined. The specification of physical dimension alone is not sufficient because time and temperature also play an intimate role. It is only when the latter two variables are fixed that failure predictions can be simplified. The sudden fracture of material with a pre-existing crack is a case in point. Barring changes in the local temperature,* the energy released to create a unit surface area of an existing crack can be obtained by considering the change in elastic energy of the system before and after crack extension. Such a quantity has been referred to as the critical energy release rate, G e, or stress intensity factor, K Ie. Other parameters, such as the crack opening displacement (COD), path-independent J-integral, etc. , have been proposed; their relation to the fracture process is also based on the energy release concept. These one-parameter approaches, however, are unable simultaneously to account for the failure process of crack initiation, propagation and onset of rapid fracture. A review on the use of G, K I, COD, J, etc. , has been made by Sih [1,2].

Modelling Rock Fracturing Processes

Modelling Rock Fracturing Processes PDF Author: Baotang Shen
Publisher: Springer Science & Business Media
ISBN: 9400769040
Category : Science
Languages : en
Pages : 181

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Book Description
This text book provides the theoretical background of rock fracture mechanics and displacement discontinuity methods used for the modelling of geomechanical problems. The computer program FRACOD is used to analyse the fracture problems, assessing fracture initiation and propagation in tension (Mode I), shear (Mode II) and mixed mode I and II of solid intact or jointed geomaterials. The book also presents the fundamentals of thermo-mechanical coupling and hydro-mechanical coupling. Formulations of multiple regional mechanical, thermal and hydraulic functions, which allow analyses of fracture mechanics problems for structures made of brittle, rock-like materials, are provided. In addition, instructive examples of code verification and applications are presented. Additional material: The 2-D version of the FRACOD program, a manual on the program and a wealth of verification examples of classical problems in physics, mechanics and hydromechanics are available at http://extras.springer.com. A large number of applications related to civil, mining, petroleum and environmental engineering are also included. - The first textbook available on modelling of rock fracture propagation - Introduces readers to the fundamentals of rock fracturing - Uses a modern style of teaching with theory, mathematical modelling and applications in one package - The basic version of the FRACOD software, manual, verification examples and applications are available as additional material - The FRACOD program and manual enable the readers to solve fracture propagation problems on their own --------------------------- Ki-Bok Min, Department of Energy Resources Engineering, College of Engineering, Seoul National University, Korea “Challenging rock engineering applications require extreme conditions of stress, temperature and hydraulic pressure resulting in rock fracturing to a various extent. The FRACOD is one of few computer codes available in engineering rock mechanics that can simulate the initiation and propagation of fractures often interacting with natural fractures. Its capability has been significantly enhanced to include the hydraulic and thermal fracturing with concerted interaction from multi-national research and industry partners. My experience with the FRACOD is very positive and I am certain that its already-excellent track record will expand further in the future."

Lost Circulation and Wellbore Strengthening

Lost Circulation and Wellbore Strengthening PDF Author: Yongcun Feng
Publisher: Springer
ISBN: 3319894358
Category : Technology & Engineering
Languages : en
Pages : 94

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Book Description
This book focuses on the underlying mechanisms of lost circulation and wellbore strengthening, presenting a comprehensive, yet concise, overview of the fundamental studies on lost circulation and wellbore strengthening in the oil and gas industry, as well as a detailed discussion on the limitations of the wellbore strengthening methods currently used in industry. It provides several advanced analytical and numerical models for lost circulation and wellbore strengthening simulations under realistic conditions, as well as their results to illustrate the capabilities of the models and to investigate the influences of key parameters. In addition, experimental results are provided for a better understanding of the subject. The book provides useful information for drilling and completion engineers wishing to solve the problem of lost circulation using wellbore strengthening techniques. It is also a valuable resource for industrial researchers and graduate students pursuing fundamental research on lost circulation and wellbore strengthening, and can be used as a supplementary reference for college courses, such as drilling and completion engineering and petroleum geomechanics.

Fracture Mechanics

Fracture Mechanics PDF Author: Chin-Teh Sun
Publisher: Academic Press
ISBN: 0123850010
Category : Technology & Engineering
Languages : en
Pages : 337

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Book Description
From a leading expert in fracture mechanics, this text provides new approaches and new applications to advance the understanding of crack formation and propagation.

Time-Dependent Fracture Mechanics

Time-Dependent Fracture Mechanics PDF Author: Dominique P. Miannay
Publisher: Springer Science & Business Media
ISBN: 9780387952123
Category : Science
Languages : en
Pages : 490

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Book Description
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.

Mechanics of Fretting Fatigue

Mechanics of Fretting Fatigue PDF Author: D.A. Hills
Publisher: Springer Science & Business Media
ISBN: 9401582815
Category : Technology & Engineering
Languages : en
Pages : 251

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Book Description
Failures of many mechanical components in service result from fatigue. The cracks which grow may either originate from some pre-existing macroscopic defect, or, if the component is of high integrity but highly stressed, a region of localized stress concentration. In turn, such concentrators may be caused by some minute defect, such as a tiny inclusion, or inadvertent machining damage. Another source of surface damage which may exist between notionally 'bonded' components is associated with minute relative motion along the interface, brought about usually be cyclic tangential loading. Such fretting damage is quite insidious, and may lead to many kinds of problems such as wear, but it is its influence on the promotion of embryo cracks with which we are concerned here. When the presence of fretting is associated with decreased fatigue performance the effect is known as fretting fatigue. Fretting fatigue is a subject drawing equally on materials science and applied mechanics, but it is the intention in this book to concentrate attention entirely on the latter aspects, in a search for the quantification of the influence of fretting on both crack nucleation and propagation. There have been very few previous texts in this area, and the present volume seeks to cover five principal areas; (a) The modelling of contact problems including partial slip under tangentialloading, which produces the surface damage. (b) The modelling of short cracks by rigorous methods which deal effectively with steep stress gradients, kinking and closure. (c) The experimental simulation of fretting fatigue.

Fracture Mechanics and Crack Growth

Fracture Mechanics and Crack Growth PDF Author: Naman Recho
Publisher: John Wiley & Sons
ISBN: 111856328X
Category : Technology & Engineering
Languages : en
Pages : 347

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Book Description
This book presents recent advances related to the following two topics: how mechanical fields close to material or geometrical singularities such as cracks can be determined; how failure criteria can be established according to the singularity degrees related to these discontinuities. Concerning the determination of mechanical fields close to a crack tip, the first part of the book presents most of the traditional methods in order to classify them into two major categories. The first is based on the stress field, such as the Airy function, and the second resolves the problem from functions related to displacement fields. Following this, a new method based on the Hamiltonian system is presented in great detail. Local and energetic approaches to fracture are used in order to determine the fracture parameters such as stress intensity factor and energy release rate. The second part of the book describes methodologies to establish the critical fracture loads and the crack growth criteria. Singular fields for homogeneous and non-homogeneous problems near crack tips, v-notches, interfaces, etc. associated with the crack initiation and propagation laws in elastic and elastic-plastic media, allow us to determine the basis of failure criteria. Each phenomenon studied is dealt with according to its conceptual and theoretical modeling, to its use in the criteria of fracture resistance; and finally to its implementation in terms of feasibility and numerical application. Contents 1. Introduction. Part 1: Stress Field Analysis Close to the Crack Tip 2. Review of Continuum Mechanics and the Behavior Laws. 3. Overview of Fracture Mechanics. 4. Fracture Mechanics. 5. Introduction to the Finite Element Analysis of Cracked Structures. Part 2: Crack Growth Criteria 6. Crack Propagation. 7. Crack Growth Prediction in Elements of Steel Structures Submitted to Fatigue. 8. Potential Use of Crack Propagation Laws in Fatigue Life Design.

The Life of Cracks

The Life of Cracks PDF Author: Srečko Glodež
Publisher: Cambridge Scholars Publishing
ISBN: 1527556549
Category : Technology & Engineering
Languages : en
Pages : 175

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Book Description
Many people find the concept of fracture and damage mechanics to be somewhat problematic, mainly because, until recently, close attention in mechanics was focused especially on the strength and resistance of materials. In this sense, to speak of fracture is as uncomfortable for some as it is to speak of a deadly disease. In confronting and preventing a fatal disease, one must understand its complexity, symptoms, and behavior; by the same token, in securing the strength of an engineering structure, one must understand the reasons and type of its potential failure. This book will provide knowledge and insights on this matter to its readers.

Hydraulic Fracture Mechanics

Hydraulic Fracture Mechanics PDF Author: Peter Valkó
Publisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 328

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Book Description
The book explores the theoretical background of one of the most widespread activities in hydrocarbon wells, that of hydraulic fracturing. A comprehensive treatment of the basic phenomena includes: linear elasticity, stresses, fracture geometry and rheology. The diverse concepts of mechanics are integrated into a coherent description of hydraulic fracture propagation. The chapters in the book are cross-referenced throughout and the connections between the various phenomena are emphasized. The book offers readers a unique approach to the subject with the use of many numerical examples.