A Dislocation-based Multiscale Modeling of Plasticity and Controlling Mechanisms

A Dislocation-based Multiscale Modeling of Plasticity and Controlling Mechanisms PDF Author: Nasrin Taheri-Nassaj
Publisher:
ISBN:
Category :
Languages : en
Pages : 163

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Book Description
The objective of this research is to investigate the plastic deformation and its controlling mechanisms in order to model and predict the material microstructure either dislocation pileups as a feature of plasticity or spatio-temporal dislocations pattern as another feature of plastic deformation using a hierarchical multiscale modeling approach from discrete dislocation dynamic to continuum dislocation dynamics and continuum mechanics.

A Dislocation-based Multiscale Modeling of Plasticity and Controlling Mechanisms

A Dislocation-based Multiscale Modeling of Plasticity and Controlling Mechanisms PDF Author: Nasrin Taheri-Nassaj
Publisher:
ISBN:
Category :
Languages : en
Pages : 163

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Book Description
The objective of this research is to investigate the plastic deformation and its controlling mechanisms in order to model and predict the material microstructure either dislocation pileups as a feature of plasticity or spatio-temporal dislocations pattern as another feature of plastic deformation using a hierarchical multiscale modeling approach from discrete dislocation dynamic to continuum dislocation dynamics and continuum mechanics.

Multiscale Modelling of Plasticity and Fracture by Means of Dislocation Mechanics

Multiscale Modelling of Plasticity and Fracture by Means of Dislocation Mechanics PDF Author: Peter Gumbsch
Publisher: Springer Science & Business Media
ISBN: 3709102839
Category : Technology & Engineering
Languages : en
Pages : 401

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Book Description
The latest state of simulation techniques to model plasticity and fracture in crystalline materials on the nano- and microscale is presented. Discrete dislocation mechanics and the neighbouring fields molecular dynamics and crystal plasticity are central parts. The physical phenomena, the theoretical basics, their mathematical description and the simulation techniques are introduced and important problems from the formation of dislocation structures to fatigue and fracture from the nano- to microscale as well as it’s impact on the macro behaviour are considered.

Multiscale Plasticity

Multiscale Plasticity PDF Author: Nasr Ghoniem
Publisher: Wiley
ISBN: 9781118410929
Category : Technology & Engineering
Languages : en
Pages : 0

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Book Description
Multiscale Plasticity Nasr M Ghoniem and Giacomo Po, UCLA, USA A comprehensive treatment of plastic deformation at multiple length scales Plastic deformation is an important subject as a result of the wide use of metals in many technological applications, the fact that it is associated with failure mechanisms, and because of the emergence of strain engineering in the microelectronics industry. Plasticity is also becoming a significant factor in the design of nano and micro systems. Multiscale Plasticity addresses the subject of plasticity in a comprehensive manner, utilizing the multiscale modelling of materials (MMM) approach to systematically reduce the degrees of freedom at natural length scales. At the atomic scale, computer simulation methods, such as Molecular Dynamics (MD) and the Kinetic Monte Carlo (KMC) are presented. The book then discusses the role played by Dislocation Dynamics (DD) and Statistical Mechanics (SM) methods in understanding microstructure self-organization, heterogeneous plastic deformation, material instabilities and failure phenomena. At the macro-scale, emphasis is placed on recent progress made in crystal plasticity, strain gradient elasticity, strain gradient plasticity, and homogenization techniques. Key Features: Presents a physically based approach to the description of plasticity. Modern computational methods are introduced to the reader at multiple length scales, from the atoms all the way up to the continuum level. Direct comparisons between experiment and multiscale modelling. Applications are given in nano and micro-technologies, as well as examples of materials-by-design. Pedagogical in nature, Multiscale Plasticity leads the reader to a more in-depth understanding of plasticity at all length scales for a wide range of applications.

Crystal Plasticity Finite Element Methods

Crystal Plasticity Finite Element Methods PDF Author: Franz Roters
Publisher: John Wiley & Sons
ISBN: 3527642099
Category : Technology & Engineering
Languages : en
Pages : 188

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Book Description
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.

Dislocation Mechanism-Based Crystal Plasticity

Dislocation Mechanism-Based Crystal Plasticity PDF Author: Zhuo Zhuang
Publisher: Academic Press
ISBN: 0128145927
Category : Technology & Engineering
Languages : en
Pages : 450

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Book Description
Dislocation Based Crystal Plasticity: Theory and Computation at Micron and Submicron Scale provides a comprehensive introduction to the continuum and discreteness dislocation mechanism-based theories and computational methods of crystal plasticity at the micron and submicron scale. Sections cover the fundamental concept of conventional crystal plasticity theory at the macro-scale without size effect, strain gradient crystal plasticity theory based on Taylar law dislocation, mechanism at the mesoscale, phase-field theory of crystal plasticity, computation at the submicron scale, including single crystal plasticity theory, and the discrete-continuous model of crystal plasticity with three-dimensional discrete dislocation dynamics coupling finite element method (DDD-FEM). Three kinds of plastic deformation mechanisms for submicron pillars are systematically presented. Further sections discuss dislocation nucleation and starvation at high strain rate and temperature effect for dislocation annihilation mechanism. Covers dislocation mechanism-based crystal plasticity theory and computation at the micron and submicron scale Presents crystal plasticity theory without size effect Deals with the 3D discrete-continuous (3D DCM) theoretic and computational model of crystal plasticity with 3D discrete dislocation dynamics (3D DDD) coupling finite element method (FEM) Includes discrete dislocation mechanism-based theory and computation at the submicron scale with single arm source, coating micropillar, lower cyclic loading pillars, and dislocation starvation at the submicron scale

Multiscale Modeling of Dislocation Processes in BCC Tantalum

Multiscale Modeling of Dislocation Processes in BCC Tantalum PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Plastic deformation in bcc metals at low temperatures and high-strain rates is controlled by the motion of a/2111 screw dislocations, and understanding the fundamental atomistic processes of this motion is essential to develop predictive multiscale models of crystal plasticity. The multiscale modeling approach presented here for bcc Ta is based on information passing, where results of simulations at the atomic scale are used in simulations of plastic deformation at mesoscopic length scales via dislocation dynamics (DD). The relevant core properties of a/2111 screw dislocations in Ta have been obtained using quantum-based interatomic potentials derived from model generalized pseudopotential theory and an ab-initio data base together with an accurate Green's-function simulation method that implements flexible boundary conditions. In particular, the stress-dependent activation enthalpy for the lowest-energy kink-pair mechanism has been calculated and fitted to a revealing analytic form. This is the critical quantity determining dislocation mobility in the DD simulations, and the present activation enthalpy is found to be in good agreement with the previous empirical form used to explain the temperature dependence of the yield stress.

Mesoscale Models

Mesoscale Models PDF Author: Sinisa Mesarovic
Publisher: Springer
ISBN: 3319941860
Category : Science
Languages : en
Pages : 344

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Book Description
The book helps to answer the following questions: How far have the understanding and mesoscale modeling advanced in recent decades, what are the key open questions that require further research and what are the mathematical and physical requirements for a mesoscale model intended to provide either insight or a predictive engineering tool? It is addressed to young researchers including doctoral students, postdocs and early career faculty,

Dislocation Dynamics and Plasticity

Dislocation Dynamics and Plasticity PDF Author: Taira Suzuki
Publisher: Springer Science & Business Media
ISBN: 364275774X
Category : Science
Languages : en
Pages : 237

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Book Description
In the 1950s the direct observation of dislocations became possible, stimulat ing the interest of many research workers in the dynamics of dislocations. This led to major contributions to the understanding of the plasticity of various crys talline materials. During this time the study of metals and alloys of fcc and hcp structures developed remarkably. In particular, the discovery of the so-called in ertial effect caused by the electron and phonon frictional forces greatly influenced the quantitative understanding of the strength of these metallic materials. Statis tical studies of dislocations moving through random arrays of point obstacles played an important role in the above advances. These topics are described in Chaps. 2-4. Metals and alloys with bcc structure have large Peierls forces compared to those with fcc structure. The reasons for the delay in studying substances with bcc structure were mostly difficulties connected with the purification techniques and with microscopic studies of the dislocation core. In the 1970s, these difficulties were largely overcome by developments in experimental techniques and computer physics. Studies of dislocations in ionic and covalent bonding materials with large Peierls forces provided infonnation about the core structures of dislocations and their electronic interactions with charged particles. These are the main subjects in Chaps. 5-7.

Multiscale Modeling of Heterogeneous Structures

Multiscale Modeling of Heterogeneous Structures PDF Author: Jurica Sorić
Publisher: Springer
ISBN: 3319654632
Category : Science
Languages : en
Pages : 374

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Book Description
This book provides an overview of multiscale approaches and homogenization procedures as well as damage evaluation and crack initiation, and addresses recent advances in the analysis and discretization of heterogeneous materials. It also highlights the state of the art in this research area with respect to different computational methods, software development and applications to engineering structures. The first part focuses on defects in composite materials including their numerical and experimental investigations; elastic as well as elastoplastic constitutive models are considered, where the modeling has been performed at macro- and micro levels. The second part is devoted to novel computational schemes applied on different scales and discusses the validation of numerical results. The third part discusses gradient enhanced modeling, in particular quasi-brittle and ductile damage, using the gradient enhanced approach. The final part addresses thermoplasticity, solid-liquid mixtures and ferroelectric models. The contents are based on the international workshop “Multiscale Modeling of Heterogeneous Structures” (MUMO 2016), held in Dubrovnik, Croatia in September 2016.

Dislocations, Mesoscale Simulations and Plastic Flow

Dislocations, Mesoscale Simulations and Plastic Flow PDF Author: Ladislas Kubin
Publisher: OUP Oxford
ISBN: 0191664545
Category : Science
Languages : en
Pages : 320

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Book Description
In the past twenty years, new experimental approaches, improved models and progress in simulation techniques brought new insights into long-standing issues concerning dislocation-based plasticity in crystalline materials. During this period, three-dimensional dislocation dynamics simulations appeared and reached maturity. Their objectives are to unravel the relation between individual and collective dislocation processes at the mesoscale, to establish connections with atom-scale studies of dislocation core properties and to bridge, in combination with modelling, the gap between defect properties and phenomenological continuum models for plastic flow. Dislocation dynamics simulations are becoming accessible to a wide range of users. This book presents to students and researchers in materials science and mechanical engineering a comprehensive coverage of the physical body of knowledge on which they are based. It includes classical studies, which are too often ignored, recent experimental and theoretical advances, as well as a discussion of selected applications on various topics.