Download or read book On Stress Collapse in Adiabatic Shear Bands written by Thomas W. Wright and published by . This book was released on 1987 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: The dynamics of adiabatic shear band formation is considered making use of a simplified thermo/visco/plastic flow law. A new numerical solution is used to follow the growth of a perturbation from initiation, through early growth and severe localization, to a slowly varying terminal configuration. Asymptotic analyses predict the early and late stage patterns, but the timing and structure of the abrupt transition to severe localization can only be studied numerically, to date. A characteristic feature of the process is that temperature and plastic strain rate begin to localize immediately, but only slowly, whereas the stress first evolves almost as if there were no perturbation, but then collapses rapidly when severe localization occurs.
Download or read book The Physics and Mathematics of Adiabatic Shear Bands written by T. W. Wright and published by Cambridge University Press. This book was released on 2002-07-22 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a research monograph on the material instability known as adiabatic shear banding which often occurs in a plastically deforming material as it undergoes rapid shearing. Plastic deformation generates heat, which eventually softens most materials with continued straining, a process which is usually unstable. In this case the instability results in thin regions of highly deformed material, which are often the sites of further damage and complete failure. The main body of the book examines a series of one-dimensional problems of increasing complexity. In this way a comprehensive and quantitative picture of the complete phenomena is built up. Particular care is taken to use well established asymptotic techniques to find simple, but universal, analytic expressions or scaling laws that encapsulate various aspects of the dynamic formation and the final morphology of shear bands. A fully developed mechanics of shear is just beginning to emerge as a major companion to fracture mechanics, this book may speed the process along.
Download or read book Some Aspects of Adiabatic Shear Bands written by Thomas W. Wright and published by . This book was released on 1987 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: A one-dimensional continuum formulation for the initiation and growth of adiabatic shear bands is reviewed, including some remarks on the underlying assumptions. A short description of some perturbation calculations introduces the idea of stress collapse and band formation as a bifurcation from homogeneous deformation, and an approach for estimating the critical time of collapse for infinitesimal perturbations is introduced. Steady solutions are exhibited and their interpretation as central boundary layers is suggested. Finally it is shown that in a certain limit shear bands occur following a hyperbolic to elliptic transition in the governing equation, and in a concluding remark dipolar plasticity is introduced as a possible alternative continuum description.
Download or read book Approximate Analysis for the Formation of Adiabatic Shear Bands written by and published by . This book was released on 1990 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: Parametric solutions are given for the formation of adiabatic shear bands in the context of the one-dimensional, nonlinear theory where inertia and elasticity are ignored. When heat condition is also ignored, the exact solution reduces completely to a sequence of quadratures. For a perfectly plastic material with heat conduction, an implicit parametic solution is also constructed. This is similar to the previous one in many ways, but now it involves two quadratures; a single nonautonomous, first-order ODE; and two functions that obey heat equations. This solution appears to be very accurate (compared to the full-finite element solution) until the time of stress collapse. Results indicate that for weak rate hardening of the power-law type, intense localization depends strongly on the initial characteristics. Within the context of rigid/perfect plasticity, a scaling law for the critical strain is given, and a figure of merit is defined that ranks materials according to their tendency to form adiabatic shear bands. (JG).
Download or read book Adiabatic Shear Localization written by Bradley Dodd and published by Elsevier. This book was released on 2012-05-22 with total page 469 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rev. ed. of: Adiabatic shear localization / Y. Bai and B. Dodd. 1992. 1st ed.
Download or read book Adiabatic Shear Localization written by Bradley Dodd and published by Elsevier. This book was released on 2012-05-22 with total page 469 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adiabatic shear localization is a mode of failure that occurs in dynamic loading. It is characterized by thermal softening occurring over a very narrow region of a material and is usually a precursor to ductile fracture and catastrophic failure. This reference source is the revised and updated version of the first detailed study of the mechanics and modes of adiabatic shear localization in solids. Building on the success of the first edition, the book provides a systematic description of a number of aspects of adiabatic shear banding. The concepts and techniques described in this work can usefully be applied to solve a multitude of problems encountered by those investigating fracture and damage in materials, impact dynamics, metal working and other areas. Specific chapters focus on energetic materials, polymers, bulk metal glasses, and the mathematics of shear banding as well as the numerical modeling of them. With its detailed coverage of the subject, this book is of great interest to academics and researchers into materials performance as well as professionals. Up-to-date coverage of the subject and research that has occurred over the past 20 years Each chapter is written on a different sub-field of adiabatic shear by an acknowledged expert in the field Detailed and clear discussions of each aspect
Download or read book Dynamic Damage and Fragmentation written by David Edward Lambert and published by John Wiley & Sons. This book was released on 2019-01-14 with total page 439 pages. Available in PDF, EPUB and Kindle. Book excerpt: Engineering structures may be subjected to extreme high-rate loading conditions, like those associated with natural disasters (earthquakes, tsunamis, rock falls, etc.) or those of anthropic origin (impacts, fluid–structure interactions, shock wave transmissions, etc.). Characterization and modeling of the mechanical behavior of materials under these environments is important in predicting the response of structures and improving designs. This book gathers contributions by eminent researchers in academia and government research laboratories on the latest advances in the understanding of the dynamic process of damage, cracking and fragmentation. It allows the reader to develop an understanding of the key features of the dynamic mechanical behavior of brittle (e.g. granular and cementitious), heterogeneous (e.g. energetic) and ductile (e.g. metallic) materials.
Download or read book On the Measurement of Local Strain and Temperature During the Formation of Adiabatic Shear Bands in Steels written by Y. C. Chi and published by . This book was released on 1969 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental study was conducted to determine local strain, local strain rate, and temperature distribution within an adiabatic shear band during its formation. Thin-walled tubular specimens were deformed at dynamic rates in a torsional Kolsky bar (torsional split-Hopkinson bar) and direct observation of the strain localization process was made through ultra high-speed photography of a grid pattern deposited on the specimen's surface. Temperature measurements were effected using an array of sixteen infrared radiation detectors. The optical system employed allows each detector to focus on a band 17 micrometers wide. Three different steels were tested: (1) an AISI 1018 cold rolled steel, (2) a low alloy structural steel (HY-100), and (3) an AISI 4340 VAR steel tempered to either of two hardnesses, HRC 44 or 55. The principal goal of the investigation was to relate initial geometric defects in specimen geometry to the timing of stress collapse during shear band development. A comparison of experimental results with predictions based on the analysis of Molinari and Clifton showed good agreement. In addition, quasi-static tests on the same materials revealed two significant differences between dynamic and quasi-static plastic deformation. First, localization of strain into a shear band occurs in dynamic deformation, but never quasi-statically, and second, the magnitude of the strain fracture is always considerably greater in quasi-static deformation than dynamically. (kt).
Download or read book Stress Concentrators and Rate Effects in Formation of Adiabatic Shear Bands written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Final Technical Report covers the contract period from 7 Nov 96 to 6 Jan 98. A more detailed information on the progress of this Contract can be found in the previous Interim Reports. During the period under consideration the research has been continued on analyses of experimental results obtained via the Modified Double Shear experimental technique (MDS). This technique has been applied for VAR 4340 steel with the heat treatment to -50 HRC. In order to study the effect of stress concentrators in shear at different rates of loading four MDS geometries have been tested with different stress concentrators, from "standard" geometry to a very sharp notch. A wide loading rate spectrum has been covered, from quasi-static to impact (up to impact velocity 100 m/s). Experiments confirmed that the adiabatic stress concentrators accelerate failure in shear. This mechanism leads to a decrease of the fragmentation energy when the impact velocity is increased. In parallel, the numerical studies for all four geometries have been performed using the FE code ABAQUS. Details of the numerical studies are given in the appendix to this Report. The numerical analyses have confirmed all observations from experiments.
Download or read book Das Gebet an der Ostsee written by and published by . This book was released on 1880 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Introduction To Adiabatic Shear Localization Revised Edition written by Bradley Dodd and published by World Scientific Publishing Company. This book was released on 2014-08-14 with total page 469 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adiabatic shear bands are found in a variety of metals and other materials; they cause rapid weakening due to energy concentration into narrow regions of the material. This is the very first book on this important topic and the only true introduction to the subject. An enhanced and updated student-friendly edition of the authors' 1992 book Adiabatic Shear Localization: Occurrence, Theories and Applications, this seminal text now includes essential Further Reading sections in some chapters. It explains adiabatic shear bands in a descriptive rather than a mathematical way, with a ‘quick reference’ section for readers wanting a more rapid introduction. Entirely comprehensive, the reader can dip into the chapters as suits his or her course material or research.If you are a postgraduate materials scientist, engineer, physicist, metallurgist, or indeed any researcher in materials that undergo rapid deformation and failure, this text is not to be missed.
Download or read book Dynamic Behavior of Materials written by Marc A. Meyers and published by John Wiley & Sons. This book was released on 1994-10-28 with total page 694 pages. Available in PDF, EPUB and Kindle. Book excerpt: Addresses fundamentals and advanced topics relevant to the behavior of materials under in-service conditions such as impact, shock, stress and high-strain rate deformations. Deals extensively with materials from a microstructure perspective which is the future direction of research today.
Download or read book Meshfree Particle Methods written by Shaofan Li and published by Springer Science & Business Media. This book was released on 2007-03-07 with total page 509 pages. Available in PDF, EPUB and Kindle. Book excerpt: Meshfree Particle Methods is a comprehensive and systematic exposition of particle methods, meshfree Galerkin and partitition of unity methods, molecular dynamics methods, and multiscale methods. Most theories, computational formulations, and simulation results presented are recent developments in meshfree methods. They were either just published recently or even have not been published yet, many of them resulting from the authors ́ own research. The presentation of the technical content is heuristic and explanatory with a balance between mathematical rigor and engineering practice. It can be used as a graduate textbook or a comprehensive source for researchers, providing the state of the art on Meshfree Particle Methods.
Download or read book Additive and Traditionally Manufactured Components written by Joshua Pelleg, PhD and published by Elsevier. This book was released on 2020-05-14 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt: Additive and Traditionally Manufactured Components: A Comparative Analysis of Mechanical Properties looks at the mechanical properties of materials produced by additive manufacturing (AM) and compares them with conventional methods. Since the production of objects by AM techniques can used in a broad array of materials, the alloys presented are the ones most commonly produced by AM - Al alloys, Ti alloys and steel. The book explores the six main types of techniques: Fused Deposition Method (FDM), Powder Bed Fusion (PBF), Inkjet Printing, Stereolithography (SLA), Direct Energy Deposition (DED) and Laminated Object Manufacturing (LOM), and follows with the techniques being utilized for fabrication. Testing of AM fabricated specimens, including tension, compression and hardness is included, along with a comparison of those results to specimens obtained by conventional fabrication methods. Topics covered include static deformation, time dependent deformation (creep), cyclic deformation (fatigue) and fracture in specimens. The book concludes with a review of the mechanical properties of nanoscale specimens obtained by AM. Thoroughly explores AM processes that can be utilized for experimental design Includes a review of dislocations observed in specimens obtained by AM Compares the impact of both additive and traditional manufacturing techniques on the mechanical properties of materials
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 Adiabatic Shear Localization written by Yilong Bai and published by Pergamon. This book was released on 1992-01-01 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adiabatic shear localization is a mode of failure that occurs in dynamic loading. It is characterized by thermal softening occurring over a very narrow region of a material and is usually a precursor to ductile fracture and catastrophic failure. This reference source is the first detailed study of the mechanics and modes of adiabatic shear localization in solids, and provides a systematic description of a number of aspects of adiabatic shear banding. The inclusion of the appendices which provide a quick reference section and a comprehensive collection of thermomechanical data allows rapid access and understanding of the subject and its phenomena. The concepts and techniques described in this work can usefully be applied to solve a multitude of problems encountered by those investigating fracture and damage in materials, impact dynamics, metal working and other areas. This reference book has come about in response to the pressing demand of mechanical and metallurgical engineers for a high quality summary of the knowledge gained over the last twenty years. While fulfilling this requirement, the book is also of great interest to academics and researchers into materials performance.
Download or read book IUTAM Symposium on New Applications of Nonlinear and Chaotic Dynamics in Mechanics written by Francis C. Moon and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 559 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the latest research results in the area of applied nonlinear dynamics and chaos theory. Papers by three academic generations address new applications of nonlinear dynamics to mechanics, including fluid-structure interaction, machining and mechanics of solids, and many other applications.
