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Book Constraint Effect in Brittle Fracture

Download or read book Constraint Effect in Brittle Fracture written by Y-J Chao and published by . This book was released on 1997 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Variation of apparent fracture toughness under predominantly (elastic) brittle fracture is investigated. Williams' asymptotic series solutions, including higher order terms, are used to characterize the crack tip stress and strain fields for various specimen geometries. Using a fracturing stress or a strain as the material property, it is demonstrated that a fracture event can be quantified by two mechanics parameters, K and A3 for stress-controlled fracture or K and T for strain-controlled fracture. A set of test data that covers a wide range of T and A3 is used to demonstrate the proposed fracture assessment procedure. Constraint-related issues such as size, crack depth, and biaxial stress effect are investigated. The material's failure locus is discussed relative to the ASTM recommended specimen geometries. It is shown that the ASTM in-plane size requirements place a finite-size window on the complete material failure locus. Since real structures may possess constraint levels either higher or lower than the ASTM standard test specimens, structures may fracture at an applied K either higher or lower than KIC. It is demonstrated that KIC determined according to ASTM E 399 and based on a linear elastic solution is not conservative when used to predict the fracture of specimens with low-constraint geometries. This trend is opposite to the corresponding constraint effect in cleavage fracture when the crack tip deformation at fracture is characterized by large-scale yielding.

Book Constraint Effects in Fracture

Download or read book Constraint Effects in Fracture written by E. M. Hackett and published by ASTM International. This book was released on 1993 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt: Papers presented at the symposium on [title] held in Indianapolis, Indiana, May 1991, provide a framework for quantifying constraint effects in terms of both continuum mechanics and micro-mechanical modeling approaches. Such a framework is useful in establishing accurate predictions of the fracture

Book Constraint Effects in Fracture Theory and Applications

Download or read book Constraint Effects in Fracture Theory and Applications written by Mark Kirk and published by ASTM International. This book was released on 1995 with total page 546 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book The Effects of Constraint and Residual Stress on Ductile and Brittle Fracture

Download or read book The Effects of Constraint and Residual Stress on Ductile and Brittle Fracture written by Simon Kamel and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Numerical Investigation of 3 D Constraint Effects on Brittle Fracture in SE B and C T Specimens

Download or read book Numerical Investigation of 3 D Constraint Effects on Brittle Fracture in SE B and C T Specimens written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This investigation employs 3-D nonlinear finite element analyses to conduct an extensive parametric evaluation of crack front stress triaxiality for deep notch SE(B) and C(T) specimens and shallow notch SE(B) specimens, with and without side grooves. Crack front conditions are characterized in terms of J-Q trajectories and the constraint scaling model for cleavage fracture toughness proposed previously by Dodds and Anderson. The 3-D computational results imply that a significantly less strict size/deformation limit, relative to the limits indicated by previous plane-strain computations, is needed to maintain small-scale yielding conditions at fracture by a stress- controlled, cleavage mechanism in deep notch SE(B) and C(T) specimens. Additional new results made available from the 3-D analyses also include revised [eta]-plastic factors for use in experimental studies to convert measured work quantities to thickness average and maximum (local) J-values over the crack front.

Book Effect of Crack tip Region Constraint on Fracture in the Ductile to brittle Transition

Download or read book Effect of Crack tip Region Constraint on Fracture in the Ductile to brittle Transition written by Ted L. Anderson and published by . This book was released on 1984 with total page 199 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effect of geometry on fracture toughness of steel in the ductile-to-brittle transition region has been studied. The critical crack-tip opening displacement (CTOD) and the critical J-integral have been measured as a function of temperature for ten fracture specimen configurations of ABS grade EH36 steel. A technique was developed to experimentally measure crack-tip constraint. Constraint decreased with crack blunting. This relaxation in constraint was modeled by a simple spring analog. The model was used to predict ductile-to-brittle transition curves for hypothetical structures. Some of the applications and limitations of the model are discussed.

Book CONSTRAINT EFFECT IN FRACTURE WHAT IS IT

Download or read book CONSTRAINT EFFECT IN FRACTURE WHAT IS IT written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The meaning of the phrase 'constraint effect in fracture' has changed in the past two decades from 'contained plasticity' to a broader description of 'dependence of fracture toughness value on geometry of test specimen or structure'. This paper will first elucidate the fundamental mechanics reasons for the apparent 'constraint effects in fracture', followed by outlining a straightforward approach to overcoming this problem in both brittle (elastic) and ductile (elastic-plastic) fracture. It is concluded by discussing the major difference in constraint effect on fracture event in elastic and elastic-plastic materials.

Book Topics in Fracture and Fatigue

Download or read book Topics in Fracture and Fatigue written by A.S. Argon and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fracture in structural materials remains a vital consideration in engineering systems, affecting the reliability of machines throughout their lives. Impressive advances in both the theoretical understanding of fracture mechanisms and practical developments that offer possibilities of control have re-shaped the subject over the past four decades. The contributors to this volume, including some of the most prominent researchers in the field, give their long-range perspectives of the research on the fracture of solids and its achievements. The subjects covered in this volume include: statistics of brittle fracture, transition of fracture from brittle to ductile, mechanics and mechanisms of ductile separation of heterogenous solids, the crack tip environment in ductile fracture, and mechanisms and mechanics of fatigue. Materials considered range from the usual structural solids to composites. The chapters include both theoretical points of view and discussions of key experiments. Contributors include: from MIT, A.S. Argon, D.M. Parks; from Cambridge, M.F. Ashby; from U.C. Santa Barbara, A.G. Evans, R. McMeeking; from Glasgow, J. Hancock; from Harvard, J.W. Hutchinson, J.R. Rice; from Sheffield, K.J. Miller; from Brown, A. Needleman; from the Ecole des Mines, A. Pineau; from U.C. Berkeley, R. O. Ritchie; and from Copenhagen, V. Tvergaard.

Book Modeling the Constraint Effects on Fracture Toughness of Materials

Download or read book Modeling the Constraint Effects on Fracture Toughness of Materials written by Sunil Kumar Prakash and published by . This book was released on 2009 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Cleavage fracture has been a very important subject for engineers for a long time because of the catastrophic result it may cause. The experimental results of cleavage fracture exhibit a large amount of scatter and show significant constraint effect, which motivated the development of statistical and micromechanics based methods in order to deal with such problem. The Weibull stress model, which is based on the weakest link statistics, uses two parameters, m and [sigma]u?, to describe the inherent distribution of the micro-scale cracks once the plastic deformation has occurred and to define the relationship between the macro and micro-scale driving forces for cleavage fracture. In this paper we examine constraint effects on cleavage fracture toughness numerically using a constraint function g(M) derived from the Weibull stress model. The non-dimensional function g(M) describes the evolution of constraint loss effects on fracture toughness relative to reference plane-strain small scale yielding (SSY) condition (T-stress=0). We performed detailed finite element analyses of single-edge notched bending speciments and compute g(M) functions for them. The g-function varies with parameters of the Weibull stress model, material flow properties and speciment geometry but not with absolute specimen size. Knowing the g-function one can construct fracture driving force curves for each absolute size of interest."--Abstract.

Book Analysis of Brittle Fracture in Surface Cracked Plates Using Constraint Corrected Stress Fields

Download or read book Analysis of Brittle Fracture in Surface Cracked Plates Using Constraint Corrected Stress Fields written by YY. Wang and published by . This book was released on 2003 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent work in constraint-based fracture mechanics has shown that the crack tip fields of surface-cracked plates (SCPs) can be accurately represented by J and T dominated two-parameter fields for remote loads up to general yield. When the parametric expressions of J and T are known, it is possible to have the full crack-tip fields of SCPs from the J-T dominated modified boundary layer (MBL) solutions.

Book 3 D Constraint Effects on Models for Transferability of Cleavage Fracture Toughness

Download or read book 3 D Constraint Effects on Models for Transferability of Cleavage Fracture Toughness written by RH. Dodds and published by . This book was released on 1997 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the late 1980s there has been renewed interest and progress in understanding the effects of constraint on transgranular cleavage in ferritic steels. Research efforts to characterize the complex interaction of crack tip separation processes with geometry, loading mode and material flow properties proceed along essentially two major lines of investigation: (1) multi-parameter descriptions of stationary crack-tip fields under large-scale yielding conditions, and (2) rational micromechanics models for the description of cleavage fracture which also reflect the observed scatter in the ductile-to-brittle transition (DBT) region. This article reviews the essential features of a specific example representing each approach: the J-Q extension to correlative fracture mechanics and a local approach based on the Weibull stress. Discussions focus on the growing body of 3-D numerical solutions for common fracture specimens which, in certain cases, prove significantly different from long-established plane-strain results.

Book Fatigue and Fracture

Download or read book Fatigue and Fracture written by F. C. Campbell and published by ASM International. This book was released on 2012-01-01 with total page 699 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This book emphasizes the physical and practical aspects of fatigue and fracture. It covers mechanical properties of materials, differences between ductile and brittle fractures, fracture mechanics, the basics of fatigue, structural joints, high temperature failures, wear, environmentally-induced failures, and steps in the failure analysis process."--publishers website.