Download or read book Initiation and Propagation of Shear Bands in Antiplane Shear Deformation written by F. H. Wu and published by . This book was released on 1984 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: A large block of material is subjected to a constant average strain rate resulting in deformation in the antiplane shear mode. The material is assumed to be isotropic, incompressible and hyperelastic. To simulate the situation in which strain hardening of the material is overwhelmed by thermal softening, the shear stress as a function of shear strain has a local maximum. The block contains a material imperfection in the form of a small region in which the material is less stiff than the otherwise homogeneous block, and in which the maximum possible stress is less than in the surrounding material. The transient deformation is analyzed numerically by means of the finite element method. It is found that a shear band initiates in the region of the material defect, and then propagates in a crack-like fashion into the rest of the body. A prediction of the speed of propagation of the edge of the band is made on the basis of a linearization of the governing field equations around a state corresponding to the strain level at which the local maximum in stress occurs. (Author).

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1990 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Research in Progress written by and published by . This book was released on 1983 with total page 644 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Research in Progress written by United States. Army Research Office and published by . This book was released on 1984 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vols. for 1977- consist of two parts: Chemistry, biological sciences, engineering sciences, metallurgy and materials science (issued in the spring); and Physics, electronics, mathematics, geosciences (issued in the fall).

Download or read book Transactions of the Army Conference on Applied Mathematics and Computing written by and published by . This book was released on 1989 with total page 584 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Shock Wave and High Strain Rate Phenomena in Materials written by 0 Meyers, and published by CRC Press. This book was released on 2023-07-21 with total page 1852 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings of EXPLOMET 90, the International Conference on the Materials Effects of Shock-Wave and High-Strain-Rate Phenomena, held August 1990, in La Jolla, California, represent a global and up-to-date appraisal of this field. Contributions (more than 100) deal with high-strain-rate deforma

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 Computational Analysis of Shear Band Initiation and Propagation in Zr Cu Based Bulk Metallic Glass written by Gayan A. Abeygunawardane-Arachchige and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Consideration of Microstructural Changes in the Study of Adiabatic Shear Bands written by and published by . This book was released on 1994 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have analyzed the effect of microstructural changes on the initiation and growth of shear bands. These have been studied by developing an adaptive mesh refinement technique to decipher adiabatic shear bands in two-dimensional problems, formulating a three-dimensional finite-deformation theory for dipolar thermoviscoplastic materials and using it to examine the initiation and growth of shear bands in plane strain thermomechanical deformations of dipolar materials, employing an internal variable theory of Brown, Kim and Anand to study the shear band problem, investigating the possibility of phase transformations during the development of adiabatic shear bands in a steel specimen, ascertaining the speed of propagation of a shear band in a steel tube, assessing the effect of frictional forces between the loading device and the cylinder ends, and, analyzing the development of a shear band in a FCC single crystal. Principal results obtained during these investigations are summarized in the report. (AN).

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 Government Reports Announcements Index written by and published by . This book was released on 1984 with total page 672 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Instabilit s Plastiques written by and published by . This book was released on 1985 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Initiation and Growth of Adiabatic Shear Bands written by T. W. Wright and published by . This book was released on 1985 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: A simple version of thermo/viscoplasticity theory is used to model the formation of adiabatic shear bands in high rate deformation of solids. The one dimensional shearing deformation of a finite slab is considered. For the constitutive assumptions made in this paper, homogeneous shearing produces a stress/strain response curve that always has a maximum when strain and rate hardening, plastic heating, and thermal softening are taken into account. Shear bands form if a perturbation is added to the homogeneous fields just before peak stress is obtained with these new fields being used as initial conditions. The resulting initial/boundary value problem is solved by the finite element method for one set of material parameters. The shear band grows slowly at first, then accelerates sharply, until finally the plastic strain rate in the center reaches a maximum, followed by a slow decline. Stress drops rapidly throughout the slab, and the central temperature increases rapidly as the peak in strain rate develops.

Download or read book Onset Propagation and Evolution of Strain Localization in Undrained Plane Strain Experiments on Clay written by Xingdong Wu and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The conventional triaxial test is the primary laboratory test for determining the shear strength of soils. Geotechnical field conditions such as long earth dams, long embankments, long retaining walls, strip foundations, tunnels, and buried pipelines often experience plane strain states of stress. However, stress strain and load deformation responses in plane strain loading differ considerably from responses observed in the conventional triaxial test. Research has shown that soils loaded in a plane strain state are far more sensitive to imperfections than soils tested in a conventional triaxial device. Plane strain loading leads to material instability manifested as sudden localized failure, resulting in decreased load-carrying capacity of the soil and compromised geotechnical and civil infrastructures. Although previous studies have mostly focused on granular materials, this research investigated the plane strain response of clay. An undrained plane strain compression test program was devised to investigate the effects of past stress history and strain rates on strain localization in kaolin clay. Experiments were carried out in a plane strain (or biaxial) device at Northwestern University, Evanston, Illinois. Because the device was heavily internally instrumented, strain localization progress was closely monitored throughout each biaxial test. Clay response in the biaxial test demonstrated three phases: (1) a homogenous response, (2) the onset and propagation of strain localization, and (3) the evolution of strain localization as a shear band. The duration of each phase was determined for each test, and a Lagrange strain tensor was used to obtain the evolution of volumetric and shear strains at the level of a shear band for three tests. Results revealed the development of large strains in these mesoscale structures. Furthermore, evolution of Mohr-Coulomb effective shear strength parameters was traced throughout the propagation and evolution phases by using two different methods. It showed that in clay samples, unlike in granular materials, the post-peak plateau, which is reached by deviatoric stress, corresponds to friction values that are significantly lower than the critical state values. Other researchers who used scanning electron microscope and anisotropy of magnetic susceptibility detected a significant reorientation of clay particles inside shear bands. Their findings combined with findings in this study lead to the conclusion that the sub-meso scale mechanism responsible for large shear strains and a severe reduction in effective friction is a significant reorientation of clay particles inside shear band.

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 The Relationship Between Damage and Localization written by Helen Lewis and published by Geological Society of London. This book was released on 2007 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: The many kinds of porous geomaterials (rocks, soils, concrete, etc.) exhibit a range of responses when undergoing inelastic deformation. In doing so they commonly develop well-ordered fabric elements, forming fractures, shear bands and compaction bands, so creating the planar fabrics that are regarded as localization. Because these induced localization fabrics alter the bulk material properties (such as permeability, acoustic characteristics and strength), it is important to understand how and why localization occurs, and how it relates to its setting. The concept of damage (in several uses) describes both the precursor to localization and the context within which it occurs. A key theme is that geomaterials display a strong material evolution during deformation, revealing a close linkage between the damage and localization processes. This volume assembles perspectives from a number of disciplines, including soil mechanics, rock mechanics, structural geology, seismic anisotropy and reservoir engineering. The papers range from theoretical to observational, and include contributions showing how the deformed geomaterial's emergent bulk characteristics, like permeability and seismic anisotropy, can be predicted.

Download or read book Shear Banding and Crack Propagation in Geomaterials Clays and Sands written by Adel Saada and published by . This book was released on 1998 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: Under simple and combined stresses clay and sand soils exhibit localization of deformation followed by shear banding. In clays, cracks or fissures and inclusions serve as concentrators when loads are applied to the material. The damage is in the form of one or more shear bands. It is found that for saturated clays the crack helps start shear bands but that it forms and propagates guided by the plasticity of an essentially frictional material. An inclination of 45 - 1/2 phi' with the major principal stress is generally observed. In sands, digital image processing techniques were developed and used to observe the displacements and the development and propagation of the shear bands. Such bands are distributed along the specimens and, upon bifurcation, some coalesce and result in a major band. The inclination of the bands for three sands of different granulometry was found to follow the Arthur-Vardoulakis criterion i.e. 45 + 1/4 (phi' + psi) with major principal stress; phi' and psi being the effective angle of friction and the angle of dilation respectively. Relative density and confining pressures were found to have little or no effects on this inclination. Shear and normal Strain measurements were made within the shear band which was found to change in size with particles moving in and out of it.