Download or read book Dynamic Fracture Initiation and Propagation in 4340 Steel Under Impact Loading written by Alan T. Zehnder and published by . This book was released on 1986 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamic fracture initiation and propagation in 4340 steel was investigated experimentally using the optical method of reflected caustics combined with high speed photography. A new crack propagation testing configuration consisting of a three point bend specimen loaded in a drop weight tower was used. It was found that prior to crack initiation the stress intensity factor time record calculated using the dynamic tip load and a static formula disagrees with the actual stress intensity factor measured by caustics. During crack propagation, the crack tip velocity and stress intensity factor time records varied smoothly and repeatably allowing for a straightforward interpretation of the data. The experiments show that for the particular heat treatment of 4340 steel used, the dynamic fracture propagation toughness depends on crack tip velocity through a relation that is a material property. Keywords: Dynamic fracture initiation, Dynamic crack propagation, Caustics, 4340 steel, High-speed camera, Stress-intensity factor, and Three point bend specimen.
Download or read book An Analysis Of and Some Observations On Dynamic Fracture in an Impact Test Specimen written by T. Nishioka and published by . This book was released on 1981 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerical simulations of crack-propagation histories in four cases of dynamic tear test experiments on 4340 steel are performed. The influence of the loss of contact of the specimen at various times with either the supports or the tup or both is critically examined. In each case, the variation of the dynamic K-factor, for the simulated crack-propagation history, is directly computed. The results are discussed in the light of current controversies surrounding the dynamic fracture toughness properties governing crack-propagation under impact loading. It is concluded that these controversies may not be fully warranted. (Author).
Download or read book Dynamic Fracture Behavior of Structural Materials written by J. H. Giovanola and published by . This book was released on 1986 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents results of a program to improve understanding of dynamic fracture behavior by investigating both crack tip loading conditions and material properties for fracture at high loading rates. A new test procedure, the one-point-bend test was analyzed and further developed the test a wide range of materials at impact loading rates. The test uses inertial loading to load the crack tip and affords an unambiguous measurement of the dynamic initiation toughness. The test's usefulness in producing small controlled increments of crack extension and in crack propagation studies was also demonstrated. Moreover, the concept of inertial loading was extended to study dynamic mixed- mode crack initiation under controlled mixed mode I and II conditions. These new test techniques were used to establish the dynamic fracture behavior of 4340 steel (HRC 50). It was shown that, for loading times to fracture as short as 20 microsecs, no time-modified criterion is necessary to predict crack initiation. The classical fracture criterion equating the applied stress intensity to the dynamic fracture toughness is adequate, provided the dynamically applied stress intensity is correctly evaluated. Under mixed mode I and II loading with (k sub II)/(k sub I) values between 0 and 0.5, it was demonstrated that dynamic crack initiation is essentially controlled by the mode I stress intensity and by the mode I dynamic fracture toughness.
Download or read book The Effects of Tempering and Test Temperature on the Dynamic Fracture Initiation Behavior of an AISI 4340 VAR Steel written by Y. C. Chi and published by . This book was released on 1988 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation was conducted into the effect of tempe ring, test temperature and loading rate on the fracture initiation behavior of an AISI 4340 VAR steel. The fracture initiation test were conducted by stress wave loading of a prefatigued circumferential crack in a notched round bar. The geometry provides for plane strain conditions at the fracture site, and the instrumentation gives records of average stress at the fracture site and of crack opening displacement, both as functions of time. Keywords: Fracture, 4340 VAR steel, fracture toughness, dynamic effects, temperature effects, microstructural effects. (jes).
Download or read book Dynamic Fracture Under Plane Wave Loading written by G. Ravichandran and published by . This book was released on 1986 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new plate impact experiment is described to study dynamic fracture processes that occur under sub-microsecond loading. The experiment is designed to make the measurements amenable to interpretation within the framework of fracture mechanics. A disc containing a mid-plane, pre-fatigued, edge crack that has been propagated halfway across the diameter is impacted by a thin flyer plate of the same material. A comprehensive pulse propagates through the specimen and reflects from the rear surface as a step, tensile pulse with a duration of 1 microsecond. This plane wave loads the crack and caused initiation and propagation of the crack. The motion of the rear surface is monitored during this event using a laser interferometer system. The location of the crack front is mapped before and after the experiment using a focussed ultrasonic transducer. Experiments have been conducted on a hardened 4340 VAR steel, at temperatures ranging from room temperature to - 100 C. Crack advance increases monotonically with increasing impact velocity and with decreasing temperature. A finite difference method is used for numerical simulation of the experiments.
Download or read book Fracture of Polymers Composites and Adhesives II written by J G Williams and published by Elsevier. This book was released on 2003-11-26 with total page 591 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fracture of Polymers, Composites and Adhesives II
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 1460 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Fracture of Structural Materials Under Dynamic Loading written by Donald A. Shockey and published by . This book was released on 1981 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: Classical concepts of Griffith-Irwin fracture mechanics were extended to include time effects and hence to apply to crack instability under dynamic loads. Theoretical considerations of the stress intensity histories experienced by cracks subjected to short pulse loads suggested that instability requires the crack tip stress intensity to exceed the dynamic toughness for a minimum time. This postulate was checked by experiments. Impact techniques were used to produce well-defined stress pulses in specimens of an epoxy, 4340 steel, 1018 steel, and 6061-T6 aluminum containing cracks of several lengths to observe crack instability behavior. The experimental results were not well described by static fracture mechanics, but were in accord with the minimum time postulates deduced from stress intensity histories. The understanding gained from the research program promises to be useful in assessing the safety of structures under dynamic loads, in characterizing the dynamic fracture resistance of materials, and in designing equipment and procedures for measuring dynamic fracture toughness. The relationship between dynamic initiation toughness and dynamic propagation toughness was addressed. The temperature histories in material near a rapidly propagating crack in a steel plate were measured and used to compute the heat of fracture and the dynamic propagation toughness. Simultaneous measurements of the dynamic stress intensity were made using the shadow optical method of caustics and high speed photography.
Download or read book Time Dependent Fracture Mechanics written by Dominique P. Miannay and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt: Intended for engineers, researchers, and graduate students dealing with materials science, structural design, and nondestructive testing and evaluation, this book represents a continuation of the author's "Fracture Mechanics" (1997). It will appeal to a variety of audiences: The discussion of design codes and procedures will be of use to practicing engineers, particularly in the nuclear, aerospace, and pipeline industries; the extensive bibliography and discussion of recent results will make it a useful reference for academic researchers; and graduate students will find the clear explanations and worked examples useful for learning the field. The book begins with a general treatment of fracture mechanics in terms of material properties and loading and provides up-to-date reviews of the ductile-brittle transition in steels and of methods for analyzing the risk of fracture. It then discusses the dynamics of fracture and creep in homogeneous and isotropic media, including discussions of high-loading-rate characteristics, the behavior of stationary cracks in elastic media under stress, and the propagation of cracks in elastic media. This is followed by an analysis of creep and crack initiation and propagation, describing, for example, the morphology and incubation times of crack initiation and growth and the effects of high temperatures. The book concludes with treatments of cycling deformation and fatigue, creep-fatigue fractures, and crack initiation and propagation. Problems at the end of each chapter serve to reinforce and test the student's knowledge and to extend some of the discussions in the text. Solutions to half of the problems are provided.
Download or read book IUTAM Symposium on Nonlinear Analysis of Fracture written by J.R. Willis and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume constitutes the Proceedings of the IUTAM Symposium on 'Nonlinear Analysis of Fracture', held in Cambridge from 3rd to 7th Septem ber 1995. Its objective was to assess and place on record the current state of understanding of this important class of phenomena, from the standpoints of mathematics, materials science, physics and engineering. All fracture phenomena are nonlinear; the reason for inclusion of this qualification in the title was to reflect the intention that emphasis should be placed on distinctive aspects of nonlinearity, not only with regard to material consti tutive behaviour but also with regard to insights gained, particularly from the mathematics and physics communities, during the recent dramatic ad vances in understanding of nonlinear systems in general. The expertise represented in the Symposium was accordingly very wide, and many of the world's greatest authorities in their respective fields participated. The Symposium remained focussed on issues of practical significance for fracture phenomena, with concentration on aspects that are still im perfectly understood. The most significant unifying issue in this regard is that of scale: this theme was addressed from several perspectives. One important aspect is the problem of passing information on one scale up or down, as an input for analysis at another scale. Although this is not always the case, it may be that the microscopic process of fracture is understood in some particular class of materials.
Download or read book Dynamics of Materials written by Lili Wang and published by Academic Press. This book was released on 2019-07-25 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamics of Materials: Experiments, Models and Applications addresses the basic laws of high velocity flow/deformation and dynamic failure of materials under dynamic loading. The book comprehensively covers different perspectives on volumetric law, including its macro-thermodynamic basis, solid physics basis, related dynamic experimental study, distortional law, including the rate-dependent macro-distortional law reflecting strain-rate effect, its micro-mechanism based on dislocation dynamics, and dynamic experimental research based on the stress wave theory. The final section covers dynamic failure in relation to dynamic damage evolution, including the unloading failure of a crack-free body, dynamics of cracks under high strain-rate, and more. - Covers models for applications, along with the fundamentals of the mechanisms behind the models - Tackles the difficult interdisciplinary nature of the subject, combining macroscopic continuum mechanics with thermodynamics and macro-mechanics expression with micro-physical mechanisms - Provides a review of the latest experimental methods for the equation of state for solids under high pressure and the distortional law under high strain-rates of materials
Download or read book Dynamic Fracture written by K. Ravi-Chandar and published by Elsevier. This book was released on 2004-10-16 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamic fracture in solids has attracted much attention for over a century from engineers as well as physicists due both to its technological interest and to inherent scientific curiosity. Rapidly applied loads are encountered in a number of technical applications. In some cases such loads might be applied deliberately, as for example in problems of blasting, mining, and comminution or fragmentation; in other cases, such dynamic loads might arise from accidental conditions. Regardless of the origin of the rapid loading, it is necessary to understand the mechanisms and mechanics of fracture under dynamic loading conditions in order to design suitable procedures for assessing the susceptibility to fracture. Quite apart from its repercussions in the area of structural integrity, fundamental scientific curiosity has continued to play a large role in engendering interest in dynamic fracture problems In-depth coverage of the mechanics, experimental methods, practical applications Summary of material response of different materials Discussion of unresolved issues in dynamic fracture
Download or read book Cracks and Fracture written by K. Bertram Broberg and published by Elsevier. This book was released on 1999-02-24 with total page 771 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cracks and Fracture consists of nine chapters in logical sequence. In two introductory chapters, physical processes in the vicinity of the crack edge are discussed and the fracture process is described. Chapter 3 develops general basic concepts and relations in crack mechanics, such as path independent integrals, stress intensity factors and energy flux into the crack edge region. Chapters 4-7 deal with elastostatic cracks, stationary or slowly moving elastic-plastic cracks, elastodynamic crack mechanics and elastoplastic aspects of fracture, including dynamic fracture mechanics. Appendices include general formulae, the basic theory of analytic functions, introduction to Laplace and Hankel transforms and description of certain basic relations, for instance for stress waves in solids. There is an extensive bibliography, containing references to both classical and recent work, and a comprehensive index. Presents an extensive bibliography containing references to both classical and recent works and a comprehensive index Appendices include general formulas, the basic theory of analytic functions, introduction to Laplace and Hankel transforms, and descriptions of certain basic relations, for instance for stress waves in solids
Download or read book Fracture Mechanics Second Edition written by Michael Janssen and published by CRC Press. This book was released on 2004-08-02 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers both theoretical and practical aspects of fracture mechanics and integrates materials science with solid mechanics.
Download or read book Dynamic Fracture Mechanics written by Arun Shukla and published by World Scientific. This book was released on 2006 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covering a wide variety of topics in dynamic fracture mechanics, this volume presents state-of-the-art experimental techniques and theoretical analysis on dynamic fracture in standard and exotic materials. Written by world renowned researchers, this valuable compendium contains eleven chapters on crack initiation, crack propagation, crack arrest, crack-stress wave interactions, and experimental, analytical and numerical methods in dynamic fracture mechanics. Contents: Modeling Dynamic Fracture Using Large-Scale Atomistic Simulations (H-J Gao & M J Buehler); Dynamic Crack Initiation Toughness (D Rittel); The Dynamics of Rapidly Moving Tensile Cracks in Brittle Amorphous Material (J Fineberg); Optical Methods for Dynamic Fracture Mechanics (H V Tippur); On the Use of Strain Gages in Dynamic Fracture (V Parameswaran & A Shukla); Dynamic and Crack Arrest Fracture Toughness (R E Link & R Chona); Dynamic Fracture in Graded Materials (A Shukla & N Jain); Dynamic Fracture Initiation Toughness at Elevated Temperatures with Application to the New Generation of Titanium Aluminides Alloys (M Shazly et al.); Dynamic Fracture of Nanocomposite Materials (A Shukla et al.). Readership: Researchers, practitioners, and graduate students in fracture mechanics and materials science.
Download or read book Applied mechanics reviews written by and published by . This book was released on 1948 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dynamic Fracture Mechanics written by L. B. Freund and published by Cambridge University Press. This book was released on 1998-03-28 with total page 592 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume focuses on the development and analysis of mathematical models of fracture phenomena.
