Download or read book Cleavage Fracture of Steel in the Ductile Brittle Transition Region written by AR. Rosenfield and published by . This book was released on 1985 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fracture-toughness experiments on ASTM A508 (Unified Numbering System [UNS] K13502) steel within the ductile-brittle transition region are a combination of both ductile and brittle behaviors, leading to severe data scatter. Both crack blunting and dimpled rupture are terminated by unstable cleavage. At a lower test temperature, cleavage during blunting predominates, whereas at a higher test temperature, cleavage tends to occur after some stable crack growth. It is suggested that this behavior results from the existence of a distribution of "trigger" sites in the microstructure (for example, inclusions and carbides). Methods for eliminating the dimpled-rupture contribution to the test record are discussed and are shown to be useful for predicting large-specimen behavior.
Download or read book Prediction of Cleavage Fracture in the Brittle to Ductile Transition Region of a Ferritic Steel written by A. Bakker and published by . This book was released on 1995 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: A model is presented to predict the event of cleavage fracture in the brittle to ductile transition region. In this region cleavage fracture could occur after some amount of ductile tearing. The model takes into account the competition between the nucleation of voids at second phase inclusions leading to ductile fracture and the nucleation of unstable micro cracks initiated at second phase inclusions leading to cleavage fracture. The model was tested on four point bend specimens of a ferritic steel tested in the brittle to ductile transition region. It was shown that there could be a significant amount of ductile crack growth before the specimens failed by cleavage. Two different crack growth simulations were performed to investigate the stresses ahead of a ductile growing crack. One simulation takes into account the softening of the material in the process zone, due to damage, around a quasistatically ductile growing crack. The second simulation neglects this damage. It was found that the crack opening stress near the crack tip in the process zone is significantly lower than in the analysis neglecting the effect of damage. Further from the crack tip, outside the damage zone the crack opening stresses are similar in both simulations.
Download or read book Stochastic Micromechanical Modeling of Cleavage Fracture in the Ductile brittle Transition Region written by David I. Auen Stienstra and published by . This book was released on 1990 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book Effects of Prior Ductile Tearing on Cleavage Fracture in the Ductile to brittle Transition Region written by Ming Tang and published by . This book was released on 1994 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental studies demonstrate a significant effect of specimen size, a/W ratio and prior ductile tearing on cleavage fracture toughness values ($Jsb{c}$) measured in the ductile-to-brittle transition region of ferritic materials. In the lower-transition region, cleavage fracture often occurs under conditions of large-scale yielding but without prior ductile crack extension. The increased toughness develops when plastic zones formed at the crack tip interact with nearby specimen surfaces which relaxes crack-tip constraint (stress triaxiality). In the mid-to-upper transition region, small amounts of ductile crack extension (typically $
Download or read book Micromechanisms and Toughness for Cleavage Fracture of Steel written by A. R. Rosenfield and published by . This book was released on 1986 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: A complete understanding of the fracture mechanisms of steel in the ductile/brittle transition region requires analysis not only of crack initiation, but also of crack propagation. This paper reviews micrographic and fractographic experiments that give insight into both phenomena, and suggests a frame-work through which both may be related. Unstable cleavage crack initiation can occur after some blunting of the original fatigue precrack or after some stable crack growth. In either event, instability appears to be triggered by the fracture of a brittle micro-constituent ahead of the precrack. The large scatter in reported KIc values within the transition region reflects the size distribution and relative scarcity of these trigger particles. While a large number of models have attempted to correlate toughness in the ductile/brittle transition regime to events occurring ahead of the crack tip, surprisingly little attention has been paid to events occurring behind the crack front. Fractographic evidence as well as metallographic sectioning of arrested cracks show that the mechanism of rapid crack propagation by cleavage is affected strongly by partial crack-plane deflection which leaves unbroken ligaments in its wake. The tearing of these ligaments by dimple-rupture is the dominant energy-absorbing mechanism. Etch-pit experiments using an Fe-Si alloy show that the crack-tip stress intensity based on plastic zone size is extremely low. Keywords: HSLA(High Strength Low Alloy), Ductile fracture, Shear fracture, Fracture toughness.
Download or read book Brittle Fracture written by and published by . This book was released on 1960 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Modeling of Ductile Tearing Effects on Cleavage Fracture Toughness written by Robert H. Dodds and published by . This book was released on 1994 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Application of the Local Approach to Fracture in the Brittle to Ductile Transition Region of Mismatched Welds written by F. Minami and published by . This book was released on 2002 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper predicts the cleavage resistance of steel welds in the ductile-to-brittle transition region by the Local Approach. Attention is payed to the strength mismatch effect on the ductile tearing and subsequent cleavage fracture. Welded joints of pipeline steels, X65 and X80 steels according to API 5L, are made with the same electrode under the same heat input condition. The resultant weld metals are matched for the X80 steel welds and overmatched for the X65 steel welds in terms of the yield strength. The fracture behavior is investigated with 3-point bend specimens and tension plate specimens with a notch in the weld metal close to the fusion line. The strength mismatch and specimen geometry exert a large influence on the cleavage toughness and prior ductile tearing; CTOD toughness and crack growth resistance for the X65 tension welds increased significantly. This is due to a loss of constraint induced by the strength overmatch and tension geometry. The fracture driving force is evaluated by the Weibull stress as a function of the crack growth. The computational cell model is applied for the analysis of crack growth, where the independence of the cell parameters on the strength mismatch and specimen geometry is verified. Using the Weibull stress fracture criterion coupled with the crack growth analysis, 3-point bend toughness results can be transferred to the fracture strength evaluation of tension loaded welds with strength mismatch in the ductile-to-brittle transition region.
Download or read book Advances in Fracture Research written by B.L. Karihaloo and published by Elsevier. This book was released on 2012-12-02 with total page 661 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fracture is a major cause of failure in metallic and non-metallic materials and structures. An understanding of the micro- and macro- mechanisms of fracture enables materials scientists to develop materials with high fracture resistance, which in turn helps engineers and designers to ensure the soundness and integrity of structures made from these materials. The International Congress on Fracture is held every four years and is an occasion to take stock of the major achievements in the broad field of fracture, to honour those who have made lasting contributions to this field, and to reflect on the future directions. ICF9 is published in six volumes covering the areas of:-- Failure Analysis, Remaining Life Assessment, Life Extension and Repair- Failure of Multiphase and Non-Metallic Materials- Fatigue of Metallic and Non-Metallic Materials and Structures- Theoretical and Computational Fracture Mechanics and New Directions- Testing and Characterization Methods, and Interfacial Fracture Mechanics- High Strain Rate Fracture and Impact Mechanics.
Download or read book Ductile Brittle Fracture Transition as a Result of Increasing In Plane Constraint in a Medium Carbon Steel written by B. Cotterell and published by . This book was released on 1994 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crack-tip opening displacement (CTOD) tests and large deformation finite element analyses have been carried out for double-edge notched tension [DE(T)] specimens with a/W = 0.9 [DE(T)9] and 0.5 [DE(T)5], single-edge notched tension [SE(T)] specimens with a/W = 0.5 [SE(T)5], three-point bend [SE(B)] specimens with a/W = 0.5 [SE(B)5] and 0.1 [SE(B)1], and center-cracked tension [M(T)] specimens with a/W = 0.5 [M(T)5]. The results of the CTOD tests show that the fracture toughness of the material decreases, and a ductile-brittle fracture transition takes place as the in-plane plastic constraint of the specimens increases. In M(T)5 and SE(B)1 specimens with low constraints, fracture is ductile and no transition occurs. In DE(T)5, SE(T)5, and SE(B)5 with higher constraints, fracture initiates by ductile tearing and then changes to cleavage. In the DE(T)9 specimens with the highest constraint, fracture initiates by brittle cleavage. The results of the finite element analyses show that the maximum achievable tensile stress outside the finite strain zone ahead of the crack tip increases with increasing plastic constraint in the order of M(T)5, SE(B)1, DE(T)5, SE(T)5, SE(B)5, and DE(T)9. The ductile-brittle transition is due to the maximum tensile stress ahead of the crack tip reaching the critical stress for cleavage fracture as the plastic constraint increases.
Download or read book Application of Fracture Toughness Scaling Models to the Ductile to brittle Transition written by R. E. Link and published by . This book was released on 1996 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanical Behavior and Fracture of Engineering Materials written by Jorge Luis González-Velázquez and published by Springer Nature. This book was released on 2019-08-29 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the theoretical concepts of stress and strain, as well as the strengthening and fracture mechanisms of engineering materials in an accessible level for non-expert readers, but without losing scientific rigor. This volume fills the gap between the specialized books on mechanical behavior, physical metallurgy and material science and engineering books on strength of materials, structural design and materials failure. Therefore it is intended for college students and practicing engineers that are learning for the first time the mechanical behavior and failure of engineering materials or wish to deepen their understanding on these topics. The book includes specific topics seldom covered in other books, such as: how to determine a state of stress, the relation between stress definition and mechanical design, or the theory behind the methods included in industrial standards to assess defects or to determine fatigue life. The emphasis is put into the link between scientific knowledge and practical applications, including solved problems of the main topics, such as stress and strain calculation. Mohr's Circle, yield criteria, fracture mechanics, fatigue and creep life prediction. The volume covers both the original findings in the field of mechanical behavior of engineering materials, and the most recent and widely accepted theories and techniques applied to this topic. At the beginning of some selected topics that by the author's judgement are transcendental for this field of study, the prime references are given, as well as a brief biographical semblance of those who were the pioneers or original contributors. Finally, the intention of this book is to be a textbook for undergraduate and graduate courses on Mechanical Behavior, Mechanical Metallurgy and Materials Science, as well as a consulting and/or training material for practicing engineers in industry that deal with mechanical design, materials selection, material processing, structural integrity assessment, and for researchers that incursion for the first time in the topics covered in this book.
Download or read book Elastic plastic Fracture Test Methods written by E. T. Wessel and published by ASTM International. This book was released on 1985 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Local Approach to Cleavage Fracture written by C S Wiesner and published by Abington Publishing. This book was released on 1995-12-14 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report assesses the current state of knowledge of the 'local approach' to cleavage fracture, reviews application to ferritic steels and their weldments and addresses limitations and disadvantages of the methodology.
Download or read book Prediction of Cleavage Fracture Probability for Ferritic Steels in the Transition Region written by V. Bicego and published by . This book was released on 1995 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: A method is described for modelling the stochastic variability of toughness data for ferritic steels in the brittle to ductile transition regime. The present model is based on two ingredients: a weakest link approach using Weibull statistics with a suitable modification to include the effect of ductile tearing, and an accurate expression of the material J-R curve, determined from fractography. The model provides a rationale for the different fracture behaviour of a material over the whole range of temperature, from fully stable J-R behaviour at high temperature down to brittle fracture under LEFM conditions at low temperature.
Download or read book Fracture Mechanics written by Ted L. Anderson and published by CRC Press. This book was released on 2017-03-03 with total page 688 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fracture Mechanics: Fundamentals and Applications, Fourth Edition is the most useful and comprehensive guide to fracture mechanics available. It has been adopted by more than 150 universities worldwide and used by thousands of engineers and researchers. This new edition reflects the latest research, industry practices, applications, and computational analysis and modeling. It encompasses theory and applications, linear and nonlinear fracture mechanics, solid mechanics, and materials science with a unified, balanced, and in-depth approach. Numerous chapter problems have been added or revised, and additional resources are available for those teaching college courses or training sessions. Dr. Anderson’s own website can be accessed at www.FractureMechanics.com.
