Download or read book Influence of Constitutive Laws on the Evolution of Micromechanical Field Variables During Deformation of FCC Metals written by Chaitali Shridhar Patil and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding spatial evolution of micromechanical fields like effective stress or effective strain during deformation of polycrystalline materials is important for the whole life cycle of structural components, starting from process optimization to damage predictions. For this purpose, crystal plasticity modelling and simulation is an important predictive tool. Validity and accuracy of these simulations depend on the choice of the constitutive law. Therefore, this study assesses influence of the constitutive laws on the full field predictions of the crystal plasticity simulations. In this regard, we analysed two different aspects of the constitutive law. Firstly, one of the main components of the constitutive law for the plastic deformation is the hardening law. In this study, therefore, we compare full field predictions using the phenomenological Voce hardening law and the dislocation density based hardening law. As functional form of these two hardening laws is different, evolution of the critical resolved shear stress of the two laws need not to be same for all orientations during the deformation. Hence, we quantified differences in the local effective stress and texture predictions of the two laws during tensile deformation of copper. Crystal plasticity simulations were performed using a three dimensional (3D) fast Fourier transform-based elasto-viscoplastic (EVP-FFT) micromechanical solver. Simulation results show that the local distribution of stress strongly depends on the hardening rule. Average texture predicted by both the laws do not vary significantly. However, spatial orientation evolution (micro-texture) varies with increasing strain. This can be attributed to the spatially different shear strain accumulation between the two laws. Dislocation densities back calculated from the critical resolved shear stress are more homogeneous in the Voce hardening law than the predictions of the dislocation density based hardening law. Finally, dislocation density based law predicts higher accumulation of the dislocation density for the grains near the 001 orientation compared to grains with other orientations. Multiple slip activity within the 001 grains can result in higher accumulation of the dislocation density, which requires further experimental validation in the future. Secondly, cross slip of the screw dislocations is one of the important mechanisms of dislocation evolution during the deformation of medium to high stacking fault energy FCC metals. In the recent literature, it has been proposed that activation energy for the cross slip depends on the applied stress state. As a result, cross slip mediated dynamic recovery of the screw dislocations will also be influenced by the applied stress state. Hence, we incorporated the stress dependent dynamic recovery of the screw dislocations in the constitutive law. We analysed influence of the dynamic recovery on the evolution of the dislocation density and the micro-texture during the tension, compression as well as plane strain compression of polycrystalline aluminium. Even with the incorporation of the stress state dependent dynamic recovery, grain average dislocation density accumulation of the 001 grains is the highest during uniaxial deformation. Hence, detailed experimental and simulation analysis of these grains is required. In case of plane strain compression, dynamic recovery of the screw dislocations increases nucleation propensity of the cube orientation ({001}100). As the sharp cube texture is commonly observed after static recrystallization of FCC materials, our results highlight importance of dynamic recovery of the screw dislocations in the dislocation density based hardening laws.

Download or read book Crystal Plasticity Finite Element Methods written by Franz Roters and published by John Wiley & Sons. This book was released on 2011-08-04 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by the leading experts in computational materials science, this handy reference concisely reviews the most important aspects of plasticity modeling: constitutive laws, phase transformations, texture methods, continuum approaches and damage mechanisms. As a result, it provides the knowledge needed to avoid failures in critical systems udner mechanical load. With its various application examples to micro- and macrostructure mechanics, this is an invaluable resource for mechanical engineers as well as for researchers wanting to improve on this method and extend its outreach.

Download or read book Advances in Constitutive Relations Applied in Computer Codes written by Janusz R. Klepaczko and published by Springer Science & Business Media. This book was released on 2010-06-10 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many important industrial applications incline toward better understanding of the constitutive properties of matter. Nowadays, the development of measurement possibilities, even in nanoscale, allows for multiscale formulations that drive to the more sophisticated models used in continuum mechanics. These phenomenological models are particularly important and useful for solutions of very concrete initial boundary value problems. Our interests are focused mainly on detailed descriptions of material behavior that depend not only on simple stress-strain relationships but also includes the strong influence of loading type, which introduces temperature, strain rate dependence, fracture, etc. Understanding these physics phenomena is of fundamental importance for successful and responsible computations. In particular, using the popular commercial programs requires deep understanding of constitutive formulations and their restrictions. These lectures are addressed to industrial users who are responsible for making crucial decisions in design, as well as, to young scientists who work on new models that describe the behavior of materials which also account the new influences and reflect the complexity of the material behavior. At the end, let me express my gratitude to the lecturers of the CISM course No. 328 on “Advances in Constitutive Relations Applied in Computer Codes”, held in Udine in July 2007, who finally prepared the included materials. Unfortunately, during the preparation and collecting papers for this book, our friend and colleague Prof. Janusz R. Klepaczko passed away. This is a very big loss for the society of mechanics.

Download or read book Advances in Structural Integrity written by Krishna Jonnalagadda and published by Springer Nature. This book was released on 2022-03-11 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book comprises the proceedings of the 3rd Structural Integrity Conference and Exhibition (SICE 2020). The contents of the volume focus on structural integrity, life prediction, and condition monitoring which are reclassified under the domains of aerospace, fracture mechanics, fatigue, creep-fatigue interactions, civil structures, experimental techniques, computation mechanics, structural health monitoring, nondestructive testing, failure analysis, materials processing, stress corrosion cracking, reliability and risk analysis. This book will be a useful reference for students, researchers and practitioners.

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1985 with total page 864 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Metals Abstracts written by and published by . This book was released on 1998 with total page 1042 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Phenomenological Micromechanical Model of FCC Metals Under Radiation Induced Crystal Defects written by Tomohito Tsuru and published by . This book was released on 2013 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crystal defects induced by irradiation obstruct dislocation movement. Hence, the critical resolved shear stress of irradiated material increases. While part of the radiation defects are swept by dislocations released from dislocation sources; therefore localization of plastic deformation are caused by a decrease of radiation defects at the partial region. In this study, in order to predict increase of flow stress due to irradiation, information of density of radiation defects is introduced into a hardening modulus of crystal plasticity. Moreover, a decrease of the work-hardening ratio is represented by considering the disappearance of the radiation defects originating in the dislocation movement. Values of the controlling parameters operating effect of the radiation defects on the flow stress are estimated by a molecular dynamics simulation. We conduct crystal plasticity simulations for copper single crystals under a simple tensile condition. The macroscopic stress-strain responses such as the increase of yield stress and the decrease of work-hardening ratio due to irradiation are numerically predicted. We investigate the effect of radiation defects and the dislocation behaviors on processes of the strain localization.

Download or read book State Variable Approach to Deformation Phenomena in FCC Metals written by Simo-Pekka Hannula and published by . This book was released on 1988 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Shock Waves and High Strain Rate Phenomena in Metals written by Mare Meyers and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 1084 pages. Available in PDF, EPUB and Kindle. Book excerpt: The scientific understanding of high-velocity deformation has advanced substantially during the past decade. On the one hand, the framework for a theory explaining the metallurgical effects of shock waves is beginning to take shape; on the other hand, the technological applications of high strain-rate processes have found their way into industries in countries around the world. Ex plosive cladding, welding, forming, compaction and consolidation, cutting, and hardening, in addition to high energy-rate deformation processes using other energy sources, are some of the topics of contemporary technological importance. Metallurgical effects are of the utmost importance in both the scientific understanding of the phenomena involved, and in the successful development and utilization of the associated applications. The international conference upon which this book is based had as its major objectives the acceleration of progress in the field of high-strain rate deformation and fabrication, including applications, by providing a forum for the exchange of state-of-the art information on the metallurgical effects of high strain-rate deformation and fabrication; and the organization of this informa tion into a timely and coherent body of knowledge focused around significant areas and applications. This volume is a manifestation of these objectives. In addition, the contents of this book were organized to provide for a somewhat logical perspective of the fundamentals, development, and state-of-the-art applications of high strain-rate and shock phenomena.

Download or read book Metallurgical Effects at High Strain Rates written by R. Rohde and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt: A conference on Metallurgical Effects at High Strain Rates was held at Albuquerque, New Mexico, February 5 through 8, 1973, under joint sponsorship of Sandia Laboratories and the Physical Metallurgy Committee of The Metallurgical Society of AIME. This book presents the written proceedings of the meeting. The purpose of the conference was to gather scientists from diverse disciplines and stimulate interdisciplinary discussions on key areas of materials response at high strain rates. In this spirit, it was similar to one of the first highly successful con ferences on this subject held in 1960, in Estes Park, Colorado, on The Response of Metals to High Velocity Deformation. The 1973 conference was able to demonstrate rather directly the increased understanding of high strain rate effects in metals that has evolved over a period of roughly 12 years. In keeping with the interdisciplinary nature of the meeting, the first day was devoted to a tutorial session of invited papers to provide attendees of diverse backgrounds with a common basis of understanding. Sessions were then held with themes centered around key areas of the high strain rate behavior of metals.

Download or read book A Constitutive Model for the Deformation Induced Anisotropic Flow of Metals written by D. C. Stouffer and published by . This book was released on 1979 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: A mathematical framework is established for the equations governing inelastic deformation under multidimensional stress state and the associated evolution equations of the internal state variables. The formulation is based on a generalization of the Prandtl-Reuss flow law. For the evolution equations it is assumed that part of the rate of change in the inelastic state variables is isotropic and the remaining part varies according to the sign and orientation of the current rate of deformation vector. This leads to a minimum of 12 components of the internal state tensor to represent the inelastic plastic flow. In this manner, both initial and load history induced plastic anisotropy can be modeled. A specific set of equations for anisotropic plastic flow is developed consistent with the inelastic state variables. (Author).

Download or read book Physics Briefs written by and published by . This book was released on 1993 with total page 1180 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Strengthening Mechanisms in Crystal Plasticity written by Ali Argon and published by Oxford University Press on Demand. This book was released on 2008 with total page 425 pages. Available in PDF, EPUB and Kindle. Book excerpt: Technologically important metals and alloys have been strengthened throughout history by empirical means. The scientific bases of the central mechanisms of such forms of strengthening, developed over the past several decades are presented here through mechanistic models and associated experimental results.

Download or read book A Review of Nonlinear Constitutive Models for Metals written by and published by . This book was released on 1990 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Comparison of the Evolution of Cold and Hot Deformation Microstructures and Textures in Fcc Metals written by and published by . This book was released on 1993 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microstructures and textures which develop during cold deformation are compared to those which develop during hot deformation. This comparison is made using the evolutionary framework of grain subdivision and the formation of low energy dislocation structures. During deformation grains are subdivided into differently deforming regions separated by geometrically necessary dislocation boundaries. These boundaries include dense dislocation walls, microbands, lamellar boundaries and subgrains. Grain subdivision occurs as a result of the requirement for strain accommodation balanced by energy considerations. This grain subdivision weakens the texture and increases the texture scatter. The tendency for grain subdivision decreases with increasing temperature of deformation with implications for the microstructural evolution and the texture formation.

Download or read book Strain Rate and History Effects on the Deformation of Metals written by K. C. Valanis and published by . This book was released on 1976 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work falls into two main categories: (i) The Endochronic Constitutive Theory and (ii) The Endochronic Theory of Fracture. Both these theories constitute significant innovations over what was the state of the art prior to their development. They are based on the concept of intrinsic time put forward by Valanis. Of far greater significance, however, is the fact that both theories have been demonstrate to be valid mathematical representations of material behavior as observed in the laboratory, and they unify, possibly for the first time constitutive and fracture behavior of metals. On the conceptual level they establish two conclusions: (a) The yield surface is not necessary for the description of plastic behavior and (b) History, yet rate independent behavior, can be formulated within the framework of the theory of thermodynamics of internal variables as formulated and developed by the principal investigator.

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt: