High-Resolution Crystal Plasticity Simulations PDF Download

Author: Martin Diehl
Publisher: Apprimus Wissenschaftsverlag
ISBN: 386359410X
Category : Technology & Engineering
Languages : en
Pages : 138

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Book Description
In this work the possibilities and capabilities of high-resolution crystal plasticity simulations are presented and discussed. Giving several examples, it is shown how the application of crystal plasticity simulations helps to understand the micro-mechanical behaviour of crystalline materials. To avoid the high computational costs associated with crystal plasticity simulations that arise from (i) the evaluation of the selected constitutive law, and (ii) the solution of the associated mechanical boundary value problem, both contributions to the runtime have to be kept small. This is done by (i) employing a rather simple—and therefore fast—constitutive model, and by (ii) using an effective spectral method employing fast Fourier transforms for solving the partial differential equations describing the mechanical behaviour. Here, an improved spectral solver incorporated into the Düsseldorf Advanced Material Simulation Kit (DAMASK) is used.

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.

Author: Wojciech Polkowski
Publisher: MDPI
ISBN: 3036508384
Category : Science
Languages : en
Pages : 438

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Book Description
The book presents a collection of 25 original papers (including one review paper) on state-of-the art achievements in the theory and practice of crystals plasticity. The articles cover a wide scope of research on materials behavior subjected to external loadings, starting from atomic-scale simulations, and a new methodological aspect, to experiments on a structure and mechanical response upon a large-scale processing. Thus, a presented contribution of researchers from 18 different countries can be virtually divided into three groups, namely (i) “modelling and simulation”; (ii) “methodological aspects”; and (iii) “experiments on process/structure/properties relationship”. Furthermore, a large variety of materials are investigated including more conventional (steels, copper, titanium, nickel, aluminum, and magnesium alloys) and advanced ones (composites or high entropy alloys). The book should be interested for senior students, researchers and engineers working within discipline of materials science and solid state physics of crystalline materials.

Author: Jörg Schröder
Publisher: Springer Science & Business Media
ISBN: 3709116252
Category : Science
Languages : en
Pages : 417

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Book Description
The book presents the latest findings in experimental plasticity, crystal plasticity, phase transitions, advanced mathematical modeling of finite plasticity and multi-scale modeling. The associated algorithmic treatment is mainly based on finite element formulations for standard (local approach) as well as for non-standard (non-local approach) continua and for pure macroscopic as well as for directly coupled two-scale boundary value problems. Applications in the area of material design/processing are covered, ranging from grain boundary effects in polycrystals and phase transitions to deep-drawing of multiphase steels by directly taking into account random microstructures.

Author: Ali Argon
Publisher: OUP Oxford
ISBN: 0191523364
Category : Science
Languages : en
Pages : 426

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Book Description
The strengthening of metals by a variety of means has been of interest over much of history. However, the elucidation of the actual mechanisms involved in the processes of alloying and work hardening, and the related processes of metals as a scientific pursuit, has become possible only through the parallel developments in dislocation theory and in definitive experimental tools of electron microscopy and X-ray diffraction. The important developments over the past several decades in the mechanistic understanding of the often complex processes of interaction of dislocations with each other, with solute atoms and with precipitates during plastic flow have largely remained scattered in the professional literature. This has made it difficult for students and professionals to have ready access to this subject as a whole. While there are some excellent reviews of certain aspects of the subject, there is presently no single comprehensive coverage available of the central mechanisms and their modelling. The present book on Strengthening Mechanisms in Crystal Plasticity provides such a coverage in a generally transparent and readily understandable form. It is intended as an advanced text for graduate students in materials science and mechanical engineering. The central processes of strengthening that are presented are modeled by dislocation mechanics in detail and the results are compared extensively with the best available experimental information. The form of the coverage is intended to inspire students or professional practitioners in the field to develop their own models of similar or related phenomena and, finally, engage in more advanced computational simulations, guided by the book.

Author: Eric Bayerschen
Publisher: KIT Scientific Publishing
ISBN: 3731506068
Category : Technology (General)
Languages : en
Pages : 278

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Book Description
In experiments on metallic microwires, size effects occur as a result of the interaction of dislocations with, e.g., grain boundaries. In continuum theories this behavior can be approximated using gradient plasticity. A numerically efficient geometrically linear gradient plasticity theory is developed considering the grain boundaries and implemented with finite elements. Simulations are performed for several metals in comparison to experiments and discrete dislocation dynamics simulations.

Author: Bingqing Cheng
Publisher:
ISBN: 9781361348031
Category :
Languages : en
Pages :

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Book Description
This dissertation, "Computer Simulations of Crystal Plasticity at Different Length Scales" by Bingqing, Cheng, 程冰清, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Crystal plasticity has been an active research field for several decades. The crystal plasticity of the bulk materials has its key relevance in the industrial process. Besides, the plasticity of nano-sized materials becomes a topic attracting a lot of interest recently. In the Part I of the thesis, molecular dynamics (MD) simulations were used to study the plasticity of small nanoparticles. Firstly, the coalescence process of Cu nanoparticles was explored. It was found that a peculiar type of five-fold twins in the sintered products were formed via an unseen before dislocation-free process involving a series of shear waves and rigid-body rotations. Secondly, a similar study on the heating of a single nanoparticle was conducted. The same dislocation-free shear wave mechanism was spotted again. In this mechanism, a cluster of atoms rearranges in a highly coordinated way between different geometrical configurations (e.g. fcc, decahedral, icosahedral) without involving dislocations. Thirdly, simulations on the sintering of many nanoparticles were performed, and the governing processes during the consolidation were discussed. The findings in this part of the thesis can provide some guidance for controlling the motifs of nanoparticles. In Part II of the thesis, the emphasis was switched to the crystal plasticity at larger spatial and temporal scales. A dislocation density-based model was developed in our research group. This model employs a dynamics formulation in which the force on each group of dislocation density is calculated with the Taylor and mutual elastic interactions taken into account. The motion of the dislocation densities is then predicted using a conservative law, with annihilation and generation considered. The new dislocation density-based model was used in this work to simulate the plastic deformation of single crystals under ultrasonic irradiation. Softening during vibrations as well as enhanced cell formation was predicted. This is the first simulation effort to successfully predict the cell formation phenomenon under vibratory loadings. DOI: 10.5353/th_b5317059 Subjects: Crystals - Plastic properties - Computer simulation

Author: Dhyanjyoti Deka
Publisher:
ISBN:
Category : Polycrystalline semiconductors
Languages : en
Pages : 232

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Book Description
Abstract: This work develops an experimentally validated computational model based on crystal plasticity for the analysis of two-phase [alpha]/[beta]Ti-6242 polycrystalline alloys. A rate dependent elasto-crystal plasticity model is incorporated in this model to accommodate anisotropy in material behavior and tension-compression asymmetry inherent to this alloy. A combination of detailed micro-testing, orientation imaging microscopy, computational simulations and minimization process involving Genetic algorithms (GA) is implemented in this study for careful characterization and calibration of the material parameters. Size effects are also considered in this analysis. A homogenized equivalent model of the transformed [beta] colonies is developed for incorporation in the Ti-6242 Finite Element (FE) model. The polycrystalline Ti-6242 computational model is constructed to incorporate accurate phase volume fractions as well as orientation distributions that are statistically equivalent to those observed in the OIM scans. The effects of accurate orientation, misorientation and micro-texture distributions are investigated through simulations using this computational model. The model is used to simulate constant strain rate and creep tests in compression and tension and the results are validated with experiments. The effects of microstructure and creep induced load-shedding on the localization of microstructural stresses and strains are studied for potential crack initiation criteria. Further, the microstructure has been studied at the point of failure in Ti-6242 in tension creep and dwell tests. Critical grains with the highest basal normal stress, stress in the loading direction and equivalent plastic strain are identified in the tension creep test and their specific crystallographic orientations and misorientations are studied. The critical grains in the case of dwell fatigue loading are also identified and a criterion for primary crack nucleation in Ti-6242 is developed.

Author: Wojciech Polkowski
Publisher: Mdpi AG
ISBN: 9783036562872
Category : Science
Languages : en
Pages : 0

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Book Description
With the second volume, we continue our mission to providing theoretical and experimental research that contribute new insights and practical findings in the field of crystal plasticity-related topics. Once again, a completely new set of 26 original works (including 22 research articles, 3 communications, and 1 review) has been collected. As in the case of the first volume, here, a full spectrum of topics belonging to the field of crystal plasticity is represented, including both numerical simulations and experimental works. By taking into account the investigated materials, the papers can be assigned to the following thematic groups: Steels and iron-based alloys; Non-ferrous alloys with fcc- (Ni- and Cu-based), or hcp crystal structure (Mg- and Ti-based). Other examples include Zirconium, Bi-Sn alloy, or polycarbonate resins; Multicomponent and high-entropy alloys; General theoretical studies on crystal plasticity. Specifically, the reprint should be interesting for students of material science and engineering, Ph.D. candidates, and researchers dealing with various theoretical and practical aspects of plastic deformation in crystalline materials.

Author: Vladimir Boyko
Publisher: Springer Science & Business Media
ISBN: 9780883188699
Category : Science
Languages : en
Pages : 328

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Book Description
Market: Research scientists and students in materials science, physical metallurgy, and solid state physics. This detailed monograph presents the theory of reversible plasticity as a new direction of development in crystal physics. It features a unique integration of traditional concepts and new studies of high- temperature superconductors, plus in-depth analyses of various related phenomena. Among the topics discussed are elastic twinning (discovered by Dr. Garber), thermoelastic martensite transformation, superelasticity, shape memory effects, the domain structure of ferroelastics, and elastic aftereffect. Partial Contents: 1. Transformation of Dislocations. Dislocation Description of a Phase Transformation Front. 2. Dislocation Theory of Elastic Twinning. Twinning of Crystals: Principal Definitions. 3. Statics and Dynamics of Elastic Twinning. Discovery of Elastic Twinning. Verification of the Validity of the Static Theory in a Description of the Macroscopic Behavior of an Elastic Twin. 4. Thermoelastic Martensitic Transformation. Martensitic Transformation: a Diffusionless Process of Rebuilding the Crystal Lattice. 5. Superelasticity and the Shape Memory Effect. Main Characteristics of Superelasticity and Shape Memory Effects. 6. Reversible Plasticity of Ferroelastics. Ferroelastics: Main Definitions. 7. Investigation of Reversible Plasticity of Crystals by the Acoustic Emission Method. Emission of Sound by Moving Dislocations andTheir Pileups. Methods Used in Experimental Investigations of the Acoustic Emission Generated by a SingleTwin. Acoustic Emission Associated with Elastic Twinning. 8. Influence of Reversible Plasticity of Superconductors on Their Physical Properties. Reversible Changes in the Parameters of Traditional Superconductors under the Action of Elastic Stresses. Influence of Magnetic Fields on Reversible Changes in the Parameters