Download or read book Evaluation of Published Data on Ductile Initiation Fracture Toughness of Low Alloy Structural Steels written by F. Ebrahimi and published by . This book was released on 1988 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Published data on ductile initiation fracture toughness, namely J-integral (Ji) and crack tip opening displacement (?i), of high-strength low-alloy steels with 275 MPa (40 ksi) minimum yield strength have been compiled along with material and testing parameters. Yield strength (?y) has been chosen as the main parameter for evaluating the compiled data. The compiled Ji and ?i data showed a large range of variation at a given strength level. In an attempt to identify the testing parameters that contribute to this variation, the compiled data have been classified into four categories: (1) valid-standard, (2) valid-nonstandard, (3) invalid-standard, and (4) invalid-nonstandard. The critical review of sorted data has revealed that (1) microstructure, (2) testing method, and (3) validity contribute to both the scatter and the behavior of Ji values as a function of yield strength. The differences observed in the behavior of various sets of data are discussed considering the physical process of ductile crack initiation at the crack tip. The correlation between Ji and ?i was investigated using linear regression analysis. The slope of the Ji/?y versus ?i plot was found to be in the range 1.7 to 2.0.

Download or read book Standard Reference Data Publications 1987 1989 written by Joan C. Sauerwein and published by . This book was released on 1989 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1977 with total page 918 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Stress weighted Damage Model for Ductile Fracture Initiation in Structural Steel Under Cyclic Loading and Generalized Stress States written by Christopher M. Smith and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fracture in steel structures represents a critical limit state in evaluating the safety and resiliency of civil infrastructure during earthquakes. This importance was demonstrated by the widespread fractures observed in older steel connections during the 1994 Northridge Earthquake, and in modern connections during the 2011 Christchurch Earthquake. The application of traditional crack-tip fracture mechanics to structural design provisions has successfully delayed the onset of Northridge-type brittle fracture. However, the extreme strain capacity in modern ductile connections increases the relevance of ductile fracture. Recent developments in 'local' fracture models have proven successful at predicting ductile fracture under many conditions. However, the application of these models has been limited due to their limited scope and difficulty in evaluation of the necessary continuum parameters. The current objective in the structural engineering community of replacing full-scale experiments with advanced finite element simulations require accurate models and calibration techniques to evaluate cyclic plasticity and fracture predictions. Motivated by the above requirements, the objectives of the present study are to (1) further the understanding of the ductile fracture mechanism for all stress, (2) develop robust methods for the calibration of constitutive parameters and local fracture models in highly plastic materials, and (3) to develop a new damage-based model to predict ductile fracture under all relevant structural conditions states (especially those with low stress triaxiality). These objectives are accomplished through an extensive experimental program, including 48 monotonic and cyclic specimens in geometries designed to effectively interrogate the fracture criteria. A total of six specimen designs are tested, including three original designs developed for the current study. Complementary finite element analyses are used to evaluate the local fracture criteria, and micrographic examination and void cell simulations provide insight into the fracture mechanism at varying stress states. The data from these experiments and the derived fracture model demonstrate the importance of the deviatoric stress state, in addition to the hydrostatic pressure, in the fracture ductility of steel. Specifically, material in a plane strain condition is found to exhibit about 50\% more fracture ductility than material in an axisymmetric stress condition. Through meta-analysis of test data from this and previous studies, ductile fracture is found to be prohibited under negative (compressive) hydrostatic pressure.

Download or read book Metals Abstracts written by and published by . This book was released on 1995 with total page 1192 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analysis of Fracture Toughness Mechanism in Ultra fine grained Steels written by Toshihiro Hanamura and published by Springer. This book was released on 2014-09-04 with total page 71 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, advanced steel technologies mainly developed at the National Institute for Materials Science (NIMS), Japan, for structure control, mechanical properties, and the related mechanisms are introduced and discussed. NIMS has long worked on developing advanced steel techniques, namely, producing advanced steels by using only simple alloying elements such as carbon, manganese, and silicon, and also by utilizing steel scrap. The hope is that this approach will lead to a technology of a so-called steel-to-steel recycling process, with the ultimate goal of a recycling process such as an automotive-steel-to-automotive-steel recycling process to take the place of the current cascade-type recycling system. The main idea is to utilize ultra-grain refining structures and hetero structures as well as martensite structures. In particular, the focus of this book is on tensile strength and toughness of advanced steels from both the fundamental and engineering points of view. Fundamentally, a unique approach to analysis is taken, based on fracture surface energy as effective grain size is employed to better understand the mechanism of property improvement. From the engineering point of view, in fracture toughness such factors as crack tip opening displacement (CTOD) of advanced steels are evaluated in comparison with those of conventional steels.

Download or read book Characterization of Materials 2 Volume Set written by Elton N. Kaufmann and published by Wiley-Interscience. This book was released on 2003-01-31 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt: Characterization of Materials (formerly Methods in Materials Research) provides comprehensive up-to-date coverage of materials characterization techniques including computational and theoretical methods as well as crystallography, mechanical testing, thermal analysis, optical imaging and spectroscopy, and more. Editor-in-Chief, Elton Kaufmann, Ph.D. is Associate Director of the Strategic Planning Group at the Argonne National Laboratory and has published approximately 100 technical papers in refereed journals and books. Dr. Kaufmann has assembled leading experts from academia, government, and industry to provide: A comprehensive up-to-date collection of methods used in the characterization of materials Articles on various methods from standard to cutting edge Periodic online updates to keep pace with latest developments A user-friendly format that is easy and simple to search and navigate Characterization of Materials is a collection of characterization methods that is widely applicable in the wide and diverse field of materials research irrespective of discipline or ultimate application and with which researchers, engineers, and educators must have familiarity. Methods covered include: General Vacuum Techniques X-Ray Powder Diffraction High Strain Rate Testing Deep Level Transient Spectroscopy Cyclic Voltammetry Extended X-Ray Absorption Fine Structure Low Energy Electron Diffraction Thermogravimetric Analysis Magnetometry Transmission Electron Microscopy Ultraviolet Photoelectron Spectroscopy This reference work is also available as a convenient online edition. For information regarding the online edition, please visit: www.mrw.interscience.wiley.com/com

Download or read book Fracture Toughness Predictions for Modern Low carbon High strength Steels Based on Microstructural and Micromechanistic Approaches written by and published by . This book was released on 2002 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NBS Special Publication written by and published by . This book was released on 1968 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Bibliographic Index written by and published by . This book was released on 1989 with total page 824 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Local Approach to Dynamic Fracture Toughness Evaluation written by T. Ochiai and published by . This book was released on 2000 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fracture toughness properties of structural steels of 490-MPa strength class and weld metals under dynamic loading are studied in the light of the near crack tip stress fields. The loading rate in toughness tests range from 0.1 to 500 mm/s. The near-tip stress fields are analyzed by 3D-FEM considering the strain rate effect on the flow properties of materials. Temperature rise caused by high-speed plastic deformation is also included in the FE analysis. The critical CTOD at brittle fracture initiation decreases when increasing the loading rate. This is due to the elevation of a local stress near the crack tip. The local approach is applied to the dynamic fracture toughness evaluation. It is shown that the brittle fracture resistance evaluated in terms of the Weibull stress, an integrated stress over a highly stressed region near the crack tip, is a material property independent of the loading rate. Based on the Weibull stress fracture criterion, the dynamic fracture toughness can be predicted from static toughness results. An engineering procedure to estimate the loading rate effect on the fracture toughness is also presented.

Download or read book The Engineering Index Annual written by and published by . This book was released on 1993 with total page 2264 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since its creation in 1884, Engineering Index has covered virtually every major engineering innovation from around the world. It serves as the historical record of virtually every major engineering innovation of the 20th century. Recent content is a vital resource for current awareness, new production information, technological forecasting and competitive intelligence. The world?s most comprehensive interdisciplinary engineering database, Engineering Index contains over 10.7 million records. Each year, over 500,000 new abstracts are added from over 5,000 scholarly journals, trade magazines, and conference proceedings. Coverage spans over 175 engineering disciplines from over 80 countries. Updated weekly.

Download or read book Evaluation of the Fracture Toughness of Ductile Iron Using Fatigue Precracked Charpy Dynamic Tear and Compact Tension Specimens written by WL. Bradley and published by . This book was released on 1988 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fracture toughness of ductile iron has been studied using dynamic tear, fatigue precracked (FPC) Charpy, and compact tension (CT) specimens. Specimens were fractured both quasi-statically and dynamically. Initial crack extension was found to occur at maximum load for both the compact tension specimens and the FPC Charpy specimens. However, initial crack extension occurred prior to maximum load for the dynamic tear specimens. Upper-shelf KJIc values determined from the compact tension specimens and the FPC Charpy specimens were similar (83 and 76 MPa ?m) while the J-value at maximum load for the dynamic tear specimens was found to fit nicely on the J-R curve from the CT specimens. The shift in ductile-to-brittle transition temperature with strain rate (comparing quasi-static with impact loading) was similar to what has been observed for structural steel with a similar yield strength.

Download or read book Influence of Material and Constraint Variation on the Fracture Toughness Behaviour of Steels written by Robert Kulka and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The analysis of fracture toughness test data from standard specimens is often based upon the assumptions of planar crack fronts and homogenous material properties. However, these assumptions do not hold true for all test geometries or real components. The overall objective of this EngD was therefore to develop the methodologies used in fracture assessment of steel components, by incorporating a reduction in the conservatisms inherent in the assessment procedures. These conservatisms are associated with applying a 'lower bound' treatment to steel components, which in reality contain significant variability in effective fracture toughness, due to either material considerations (macroscopic or microstructural), or geometrical considerations including the effect of crack tip constraint. The first method developed allows a comparison of a variation of fracture toughness values throughout a component, to a variation of the localised effective crack driving force. The main feature of this method takes advantage of the nature of the ductile-to-brittle transition regime of fracture toughness, where there is significant scatter. This leads to a probabilistic prediction of the location of fracture initiation, and a less conservative estimate of failure load, used to derive enhanced fracture toughness for the component. The second method calculates less conservative fracture toughness values for steels where there is significant heterogeneity in the dataset. The effects of measurement uncertainty on derived fracture toughness values can be monitored to improve probabilistic estimates of the heterogeneous fracture toughness values. These methods have been developed into predictive software tools, validated against data from the literature. Finite element analysis of various configurations of compact tension and bend specimen, under different constraint conditions, was used to identify fracture mechanics parameters and constraint factors that will be of use in deriving accurate fracture toughness relationships from future testing programmes. The viability of low constraint specimens for accurately characterising increases in fracture toughness has been assessed. These recommendations enhance the relationships and advice suggested in the testing standards and literature. Loss of constraint in thin components can be quantified by a triaxiality parameter, which can be used to predict an increase in fracture toughness through use of a damage model, in this case developed based on a ductility exhaustion approach. This model can be used to predict initiation of ductile fracture in configurations with low constraint, leading to less conservative fracture toughness values, enhancing the guidance in the various defect tolerance assessment procedures.

Download or read book Metallurgical Origins of Fracture Toughness and Microstructure and Fracture Toughness of an HSLA High Strength Low Alloy Steel written by A. R. Rosenfield and published by . This book was released on 1985 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report discusses effects of composition and heat treatment on the fracture behavior of a group of steels based on ASTM A712A. Very low transition temperatures were observed in a number of cases. However, adverse effects of Cu on the K sub Ic value for cleavage and on the sharpness of the ductile/brittle transition are noted. At ambient temperatures, overaged Cu particles are beneficial for ductile fracture resistance. A new experimental method of evaluating the relative contributions of opening and shear to ductile crack growth was developed, along with a superdislocation model of the process. Keywords: Steel, high-strength/low alloy; Microstructural effects; Compositional effects; Fracture statistics; Constitutive Modelling.

Download or read book Bibliography on the Brittle Fracture of Iron and Steel at Cryogenic to Room Temperatures written by and published by . This book was released on 1969 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Energy Research Abstracts written by and published by . This book was released on 1994-12 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt: