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

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.

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:

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.

Download or read book Constraint Effect on Three dimensional Elastic plastic Fracture written by Yil Kim and published by . This book was released on 2003 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

Download or read book Effects of Constraint on Elastic plastic Fracture and Ductile brittle Fracture Transition written by Cheng Yan and published by . This book was released on 1997 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Crack tip Region Constraint on Fracture in the Ductile to brittle Transition written by T. L. Anderson and published by . This book was released on 1984 with total page 199 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Constraint Effects on Fracture Toughness written by and published by . This book was released on 2001 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt: The crack growth resistance (toughness) of a structural material depends on the geometry of the crack and the type of loading. These produce differences in the crack tip stress state referred to as the constraint. The stress state controls the deformation required to initiate fracture, and the mechanisms of fracture in steels are profoundly affected by the local constraint. This report describes the crack tip behaviour of 350WT ship steel, based on tests that characterized the fracture toughness of a ship steel plate over a range of constraint conditions. The tests were performed at room temperature on three-point bend bars that were pre-cracked to different crack depths. The mode of fracture was ductile tearing and resistance curves were calculated. Results for initiation toughness and growth resistance are characterized in both the linear elastic and elastic plastic formats. In addition, finite element modelling was used to determine numerically the crack tip stress fields, with special attention to the crack tip blunting behaviour.

Download or read book Constraint Effects on Fracture Behavior written by J. A. Smith and published by . This book was released on 1997 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effect of Crack tip Region Constraint on Fracture in the Ductile to brittle Transition Region written by T. L. Anderson and published by . This book was released on 1983 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

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.

Download or read book Geometry and Constraint Effects in Mixed Mode Fracture written by Majid Reza Ayatollahi and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fracture Mechanics written by Walter G. Reuter and published by ASTM International. This book was released on 1995 with total page 842 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Relationship Between Constraint and Ductile Fracture Initiation as Defined by Micromechanical Analyses written by TL. Panontin and published by . This book was released on 1995 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall objective of this study is to provide a proven methodology to allow the transfer of ductile fracture initiation properties measured in standard labora tory specimens to large, complex, flawed structures. A significant part of this work involved specifically addressing effects of constraint on transferability under large scale yielding conditions. The approach taken was to quantify constraint effects through micro-mechanical fracture models coupled with finite element generated crack tip stress-strain fields to identify the local condition corresponding to fracture initiation. Detailed finite element models predicted the influence of specimen geometry, loading mode, and material flow properties on the crack tip fields.

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: