Methods of Analysis and Solutions of Crack Problems

Methods of Analysis and Solutions of Crack Problems PDF Author: George C. Sih
Publisher: Springer Science & Business Media
ISBN: 9401722609
Category : Science
Languages : en
Pages : 562

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Book Description
It is weH known that the traditional failure criteria cannot adequately explain failures which occur at a nominal stress level considerably lower than the ultimate strength of the material. The current procedure for predicting the safe loads or safe useful life of a structural member has been evolved around the discipline oflinear fracture mechanics. This approach introduces the concept of a crack extension force which can be used to rank materials in some order of fracture resistance. The idea is to determine the largest crack that a material will tolerate without failure. Laboratory methods for characterizing the fracture toughness of many engineering materials are now available. While these test data are useful for providing some rough guidance in the choice of materials, it is not clear how they could be used in the design of a structure. The understanding of the relationship between laboratory tests and fracture design of structures is, to say the least, deficient. Fracture mechanics is presently at astandstill until the basic problems of scaling from laboratory models to fuH size structures and mixed mode crack propagation are resolved. The answers to these questions require some basic understanding ofthe theory and will not be found by testing more specimens. The current theory of fracture is inadequate for many reasons. First of aH it can only treat idealized problems where the applied load must be directed normal to the crack plane.

Methods of Analysis and Solutions of Crack Problems

Methods of Analysis and Solutions of Crack Problems PDF Author: George C. Sih
Publisher: Springer Science & Business Media
ISBN: 9401722609
Category : Science
Languages : en
Pages : 562

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Book Description
It is weH known that the traditional failure criteria cannot adequately explain failures which occur at a nominal stress level considerably lower than the ultimate strength of the material. The current procedure for predicting the safe loads or safe useful life of a structural member has been evolved around the discipline oflinear fracture mechanics. This approach introduces the concept of a crack extension force which can be used to rank materials in some order of fracture resistance. The idea is to determine the largest crack that a material will tolerate without failure. Laboratory methods for characterizing the fracture toughness of many engineering materials are now available. While these test data are useful for providing some rough guidance in the choice of materials, it is not clear how they could be used in the design of a structure. The understanding of the relationship between laboratory tests and fracture design of structures is, to say the least, deficient. Fracture mechanics is presently at astandstill until the basic problems of scaling from laboratory models to fuH size structures and mixed mode crack propagation are resolved. The answers to these questions require some basic understanding ofthe theory and will not be found by testing more specimens. The current theory of fracture is inadequate for many reasons. First of aH it can only treat idealized problems where the applied load must be directed normal to the crack plane.

Solution of Crack Problems

Solution of Crack Problems PDF Author: D.A. Hills
Publisher: Springer Science & Business Media
ISBN: 9401586489
Category : Science
Languages : en
Pages : 314

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Book Description
This book is concerned with the numerical solution of crack problems. The techniques to be developed are particularly appropriate when cracks are relatively short, and are growing in the neighbourhood of some stress raising feature, causing a relatively steep stress gradient. It is therefore practicable to represent the geometry in an idealised way, so that a precise solution may be obtained. This contrasts with, say, the finite element method in which the geometry is modelled exactly, but the subsequent solution is approximate, and computationally more taxing. The family of techniques presented in this book, based loosely on the pioneering work of Eshelby in the late 1950's, and developed by Erdogan, Keer, Mura and many others cited in the text, present an attractive alternative. The basic idea is to use the superposition of the stress field present in the unfiawed body, together with an unknown distribution of 'strain nuclei' (in this book, the strain nucleus employed is the dislocation), chosen so that the crack faces become traction-free. The solution used for the stress field for the nucleus is chosen so that other boundary conditions are satisfied. The technique is therefore efficient, and may be used to model the evolution of a developing crack in two or three dimensions. Solution techniques are described in some detail, and the book should be readily accessible to most engineers, whilst preserving the rigour demanded by the researcher who wishes to develop the method itself.

Multiple Crack Problems in Elasticity

Multiple Crack Problems in Elasticity PDF Author: Y. Z. Chen
Publisher: Wit Pr/Computational Mechanics
ISBN: 9781853129032
Category : Technology & Engineering
Languages : en
Pages : 336

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Book Description
The authors investigate various integral equations for multiple crack problems in plane elasticity. Formulation of the problems is based on relevant elementary solutions in which the complex variable function method is used.

Finite Elements in Fracture Mechanics

Finite Elements in Fracture Mechanics PDF Author: Meinhard Kuna
Publisher: Springer Science & Business Media
ISBN: 9400766807
Category : Science
Languages : en
Pages : 464

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Book Description
Fracture mechanics has established itself as an important discipline of growing interest to those working to assess the safety, reliability and service life of engineering structures and materials. In order to calculate the loading situation at cracks and defects, nowadays numerical techniques like finite element method (FEM) have become indispensable tools for a broad range of applications. The present monograph provides an introduction to the essential concepts of fracture mechanics, its main goal being to procure the special techniques for FEM analysis of crack problems, which have to date only been mastered by experts. All kinds of static, dynamic and fatigue fracture problems are treated in two- and three-dimensional elastic and plastic structural components. The usage of the various solution techniques is demonstrated by means of sample problems selected from practical engineering case studies. The primary target group includes graduate students, researchers in academia and engineers in practice.

Cracked it!

Cracked it! PDF Author: Bernard Garrette
Publisher: Springer
ISBN: 3319893750
Category : Business & Economics
Languages : en
Pages : 284

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Book Description
Solving complex problems and selling their solutions is critical for personal and organizational success. For most of us, however, it doesn’t come naturally and we haven’t been taught how to do it well. Research shows a host of pitfalls trips us up when we try: We’re quick to believe we understand a situation and jump to a flawed solution. We seek to confirm our hypotheses and ignore conflicting evidence. We view challenges incompletely through the frameworks we know instead of with a fresh pair of eyes. And when we communicate our recommendations, we forget our reasoning isn’t obvious to our audience. How can we do it better? In Cracked It!, seasoned strategy professors and consultants Bernard Garrette, Corey Phelps and Olivier Sibony present a rigorous and practical four-step approach to overcome these pitfalls. Building on tried-and-tested (but rarely revealed) methods of top strategy consultants, research in cognitive psychology, and the latest advances in design thinking, they provide a step-by-step process and toolkit that will help readers tackle any challenging business problem. Using compelling stories and detailed case examples, the authors guide readers through each step in the process: from how to state, structure and then solve problems to how to sell the solutions. Written in an engaging style by a trio of experts with decades of experience researching, teaching and consulting on complex business problems, this book will be an indispensable manual for anyone interested in creating value by helping their organizations crack the problems that matter most.

Crack Analysis in Structural Concrete

Crack Analysis in Structural Concrete PDF Author: Zihai Shi
Publisher: Butterworth-Heinemann
ISBN: 9780080942223
Category : Technology & Engineering
Languages : en
Pages : 344

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Book Description
This new book on the fracture mechanics of concrete focuses on the latest developments in computational theories, and how to apply those theories to solve real engineering problems. Zihai Shi uses his extensive research experience to present detailed examination of multiple-crack analysis and mixed-mode fracture. Compared with other mature engineering disciplines, fracture mechanics of concrete is still a developing field with extensive new research and development. In recent years many different models and applications have been proposed for crack analysis; the author assesses these in turn, identifying their limitations and offering a detailed treatment of those which have been proved to be robust by comprehensive use. After introducing stress singularity in numerical modelling and some basic modelling techniques, the Extended Fictitious Crack Model (EFCM) for multiple-crack analysis is explained with numerical application examples. This theoretical model is then applied to study two important issues in fracture mechanics - crack interaction and localization, and fracture modes and maximum loads. The EFCM is then reformulated to include the shear transfer mechanism on crack surfaces and the method is used to study experimental problems. With a carefully balanced mixture of theory, experiment and application, Crack Analysis in Structural Concrete is an important contribution to this fast-developing field of structural analysis in concrete. Latest theoretical models analysed and tested Detailed assessment of multiple crack analysis and multi-mode fractures Applications designed for solving real-life engineering problems

Elastodynamic Crack Problems

Elastodynamic Crack Problems PDF Author: George C. Sih
Publisher: Springer Science & Business Media
ISBN: 9789028601567
Category : Science
Languages : en
Pages : 410

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Book Description


Plates and shells with cracks

Plates and shells with cracks PDF Author: George C. Sih
Publisher: Springer Science & Business Media
ISBN: 940101292X
Category : Science
Languages : en
Pages : 344

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Book Description
This third volume of a series on Mechanies of Fraeture deals with eraeks in plates and shelIs. It was noted in Volume 2 on three-dimensional eraek problems that additional free surfaees can lead to substantial mathematical complexities, often making the analysis unmanageable. The theory of plates and shelIs forms a part of the theory of elasticity in which eertain physieal assumptions are made on the basis that the distanee between two bounded surfaees, either fiat or eurved, is small in eomparison with the overall dimen sions of the body. In modern times, the broad and frequent applieations of plate- and shell-like struetural members have aeted as a stimulus to whieh engineers and researchers in the field of fracture meehanies have responded with a wide variety of solutions of teehnieal importanee. These eontributions are covered in this book so that the reader may gain an understanding of how analytieal treat me nt s ofplates and shells containing initial imperfeetions in the form of eraeks are earried out. The development of plate and shell theories has involved long standing controversy on the eonsisteney of omitting eertain small terms and at the same time retaining others of the same order of magnitude. This defieieney depends on the ratio of the plate or shell thiekness, h, to other eharaeteristie dimensions and eannot be eompletely resolved in view of the approximations inherent in the transverse dependence of the extensional and bending stresses.

Analysis of Cracks in Solids

Analysis of Cracks in Solids PDF Author: A. M. Khludnev
Publisher: Computational Mechanics
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 416

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Book Description
The need for progress in modelling and analysis of crack problems in solids has resulted in renewed attempts at using modern approaches to boundary value problems. By taking a different viewpoint on the traditional treatment of many problems, such as crack theory, the range that can be resolved through mathematical tools is enlarged. This book provides a fresh outlook on crack problems, displaying new methods of studying these and proposing new models for cracks in elastic and nonelastic bodies satisfying physically suitable nonpenetration conditions between crack faces. Two- and three-dimensional bodies, plates and shells with cracks are considered. Properties of solutions such as existence of solutions, regularity up to the crack faces, and convergence of solutions as parameters of a system are varying are established, while different constitutive laws such as elastic, thermoelastic and elastoplastic are also analysed. The new approach presented by the authors is intriguing because it fails to lead to violation of physical properties. In addition, the boundary conditions analysed are given in the form of inequalities, and are properly nonpenetration conditions of crack faces. Thi

Flow Visualization and Image Analysis

Flow Visualization and Image Analysis PDF Author: F.T. Nieuwstadt
Publisher: Springer Science & Business Media
ISBN: 9401126909
Category : Technology & Engineering
Languages : en
Pages : 279

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Book Description
Progress in fluid mechanics depends heavily on the availability of good experimental data which can inspire new ideas and concepts but which are also necessary to check and validate theories and numerical calculations. With the advent of new recording and image analysis techniques new and promising experimental methods in fluid flows have presented themselves which are rather newly developed techniques such as particle tracking velocimetry (PTV), particle image velocimetry (PIV) and laser fluorescene (LIF). This volume presents state-of-the-art research on these techniques and their application to fluid flow. Selected papers from the EUROMECH conference on Image Analysis are published in this volume.