Tài liệu Unified Plastic Constitutive Laws of Deformation doc

[...]... financial decisions, etc No single book can give a full presentation of all of these issues or guidance that addresses all of these concerns In this volume, we focus on the technical aspects of the constitutive laws of plastic deformation During fabrication the major manufacturing processes subject the workpiece to plastic deformation Examples of these processes are forging, coining, extrusion, metal cutting,... Preface The constitutive law of plastic deformation expresses the effects of material behavior and properties for stress analysis in the design of manufacturing technology and product service behavior, for materials testing, and for the maintenance of structural and machine components The book represents the state of the art, but the editors do not rule out other concepts of constitutive laws There... the application of these laws to this purpose It is clear from these chapters that further work must be done; plastic deformation is a very complicated process xi xii Preface The manufacturing process and product performance diagrams give a condensed schematic of the design aspects The dark boxes indicate aspects that are served by the constitutive law of plastic deformation Constitutive laws serve to... The constitutive laws are developed in the framework of unified viscoplasticity, considering only one inelastic strain We assume the existence of a viscoplastic potential in the stress space Its position, shape, and size depend on the various hardening variables We limit ourselves to the case where the potential is a given Chapter I Unified Cyclic Viscoplastic Constitutive Equations 5 function of the... components are subjected to plastic deformation: pressure tubes and turbine blades creep; the service lifetime of springs is affected by stress relaxation, which in turn is controlled by plastic deformation, and thus fatigue is controlled by it; and crack growth is associated with plastic deformation In addition, many other service conditions require an understanding of plastic deformation (Figure A) Efficient... understanding of the mechanisms that control plastic deformation, as well as the need to represent behaviors and processes for the development of improved material characteristics to tailor them for better performance Clearly, there are a variety of causes to serve, and a variety of constitutive laws are needed These laws do not contradict each other when they are developed within the principles of the other... from the constitutive laws All of these activities are carried out with the assistance of computers and depend ultimately on the understanding and ingenuity of the design and operating engineer The end result of these activities is to achieve cost efficiency while ensuring a marketable, competitive product Within the bounds of this book the authors present their understanding of the constitutive laws and... discuss the application of constitutive models under varying temperature conditions, based on the thermodynamic theory and also the modeling of metallurgical effects, such as aging, that are induced by temperature changes A CYCLIC VISCOPLASTICCONSTITUTIVE LAW This section is devoted to the presentation and development of a set of constitutive equations based on the combination of kinematic hardening... aging state variable isotropic "drag" state variable drag stress Unified Constitutive Laws of Plastic Deformation Copyright @ 1996 by Academic Press, Inc All rights of reproduction in any form reserved 2 J U Chaboche e s A n v f2, ~p ~r p q r R S or, or' T VT u Wp Ws X, X' Y Z strain tensor elastic strain tensor plastic strain or viscoplastic strain tensor thermodynamic state potential dissipation... rule defined in Section II.B.2 Let us discuss now the additional degrees of freedom that are allowed if the constitutive model is defined in terms of the two surface presentation The translation Chapter 1 UnifiedCyclic Viscoplastic Constitutive Equations 19 rule of the center of the yield surface is defined by the position and size of the bounding surface and by the image point orl on the bounding surface . h0" alt="" Unified Plastic Constitutive Laws of Deformation This Page Intentionally Left Blank I Unified Constitutive Laws of Plastic Deformation. Oval Road, London NW1 7DX Library of Congress Cataloging-in-Publication Data Unified constitutive laws of plastic deformation / edited by A.S. Krausz,