Towards Modeling the Anisotropic Behavior of Polycrystalline Materials Due to Texture Using a Second Order Structure Tensor PDF Download
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Author: Brandon Chandler Templin
Publisher:
ISBN:
Category :
Languages : en
Pages : 112
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Book Description
A material model capable of reproducing the anisotropic behavior of polycrystalline materials will prove to be useful in simulations in which directional properties are of key importance. The primary contributor to anisotropic behavior in polycrystalline materials is the development of texture through the rotation and alignment of slip systems due to plastic deformation. A large concentration of aligned slip systems will influence the glide of dislocations in the respective global deformation direction resulting in a directionally dependent flow stress. The Evolving Microstructural Model of Inelasticity (EMMI) is modified to account for evolving anisotropy due to the development of texture. Texture is characterized via a second order orientation tensor and is incorporated into EMMI through various modifications to the EMMI equations based on physical assumptions. Evolving anisotropy is captured via a static yield surface through a modification to the flow rule based on the assumption loading is entirely elastic within the yield surface. A separate modification to the EMMI equations based on physical assumptions. Evolving anisotropy is captured via a static yield surface through a modification to the flow rule based on the assumption loading is entirely elastic within the yield surface. A separate modification to EMMI captures evolving anisotropy through an apparent yield surface via a modification to the EMMI internal state variable evolution equations. The apparent yield surface is the result of a smaller yield surface translating through stress space and assumes the state of the material is disturbed at stresses much lower than indicated by experimental yield surfaces.
Author: Brandon Chandler Templin
Publisher:
ISBN:
Category :
Languages : en
Pages : 112
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Book Description
A material model capable of reproducing the anisotropic behavior of polycrystalline materials will prove to be useful in simulations in which directional properties are of key importance. The primary contributor to anisotropic behavior in polycrystalline materials is the development of texture through the rotation and alignment of slip systems due to plastic deformation. A large concentration of aligned slip systems will influence the glide of dislocations in the respective global deformation direction resulting in a directionally dependent flow stress. The Evolving Microstructural Model of Inelasticity (EMMI) is modified to account for evolving anisotropy due to the development of texture. Texture is characterized via a second order orientation tensor and is incorporated into EMMI through various modifications to the EMMI equations based on physical assumptions. Evolving anisotropy is captured via a static yield surface through a modification to the flow rule based on the assumption loading is entirely elastic within the yield surface. A separate modification to the EMMI equations based on physical assumptions. Evolving anisotropy is captured via a static yield surface through a modification to the flow rule based on the assumption loading is entirely elastic within the yield surface. A separate modification to EMMI captures evolving anisotropy through an apparent yield surface via a modification to the EMMI internal state variable evolution equations. The apparent yield surface is the result of a smaller yield surface translating through stress space and assumes the state of the material is disturbed at stresses much lower than indicated by experimental yield surfaces.
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: Claude Esling
Publisher: Trans Tech Publications Ltd
ISBN: 3038130265
Category : Technology & Engineering
Languages : en
Pages : 486
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Book Description
Volume is indexed by Thomson Reuters CPCI-S (WoS). Natural, as well as man-made, materials are often assumed to behave uniformly, exhibiting equal strength in all directions, because most of them have a polycrystalline structure. The anisotropy of the individual crystals, however, is smoothed out only in the presence of a large number of grains having a random distribution of orientations. In reality, there usually remains an anisotropy due to the existence of preferred orientations. Its magnitude depends upon the statistical distribution of grain orientations the "crystallographic texture" or, more simply, the texture. This governs the extremes, of the physical property of interest, which a single crystal of the material under consideration can exhibit in directional tests. Local variations in texture, as well as the arrangements and types of grain/phase boundaries, may give rise to inhomogeneous material properties. The texture also carries with it information on the history of a materials processing, use and misuse. A knowledge of the texture is a prerequisite for all quantitative techniques of materials characterization, and is based upon the interpretation of diffraction-peak intensities. It is also necessary to model the relationships between microstructural features and physical or mechanical properties. Therefore, the texture is of great value for quality control in a wide range of industrial applications, and in basic materials research.
Author: U. F. Kocks
Publisher: Cambridge University Press
ISBN: 9780521794206
Category : Science
Languages : en
Pages : 672
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Book Description
A successful book covering an important area of materials science, now available in paperback.
Author: M. Jono
Publisher: Elsevier
ISBN: 1483294137
Category : Technology & Engineering
Languages : en
Pages : 3510
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Book Description
Significant progress in the science and technology of the mechanical behaviour of materials has been made in recent years. The greatest strides forward have occurred in the field of advanced materials with high performance, such as ceramics, composite materials, and intermetallic compounds. The Sixth International Conference on Mechanical Behaviour of Materials (ICM-6), taking place in Kyoto, Japan, 29 July - 2 August 1991 addressed these issues. In commemorating the fortieth anniversary of the Japan Society of Materials Science, organised by the Foundation for Advancement of International Science and supported by the Science Council of Japan, the information provided in these proceedings reflects the international nature of the meeting. It provides a valuable account of recent developments and problems in the field of mechanical behaviour of materials.
Author: Roxana Gabriela Rosu
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
This thesis proposes and evaluates parametric frameworks for modelling local structure tensor (LST) fields computed on textured images. A texture's underlying geometry is described in terms of orientation and anisotropy, estimated in each pixel by the LST. Defined as symmetric non-negative definite matrices, LSTs cannot be handled using the classical tools of Euclidean geometry. In this work, two complete Riemannian statistical frameworks are investigated to address the representation of symmetric positive definite matrices. They rely on the a ne-invariant (AI) and log-Euclidean (LE) metric spaces. For each framework, a Gaussian distribution and its corresponding mixture models are considered for statistical modelling. Solutions for parameter estimation are provided and parametric dissimilarity measures between statistical models are proposed as well. The proposed statistical frameworks are first considered for characterising LST fields computed on textured images. Both AI and LE models are first employed to handle marginal LST distributions. Then, LE models are extended to describe joint LST distributions with the purpose of characterising both spatial and multiscale dependencies. The theoretical models' fit to empirical LST distributions is experimentally assessed for a texture set composed of a large diversity of patterns. The descriptive potential of the proposed statistical models are then assessed in two applications. A first application consists of texture recognition. It deals with very high resolution remote sensing images and carbonaceous material images issued from high resolution transmission electron microscopy technology. The LST statistical modelling based approaches for texture characterisation outperform, in most cases, the state of the art methods. Competitive texture classification performances are obtained when modelling marginal LST distributions on both AI and LE metric spaces. When modelling joint LST distributions, a slight gain in performance is obtained with respect to the case when marginal distributions are modelled. In addition, the LST based methods' intrinsic ability to address the rotation invariance prerequisite that arises in many classification tasks dealing with anisotropic textures is experimentally validated as well. In contrast, state of the art methods achieve a rather pseudo rotation invariance. A second application concerns LST field synthesis. To this purpose, monoscale and multiscale pyramidal approaches relying on a Markovian hypothesis are developed. Experiments are carried out on toy LST field examples and on real texture LST fields. The successful synthesis results obtained when optimal parameter configurations are employed, are a proof of the real descriptive potential of the proposed statistical models. However, the experiments have also shown a high sensitivity to the parameters' choice, that may be due to statistical inference limitations in high dimensional spaces.
Author:
Publisher:
ISBN:
Category : Mechanics, Applied
Languages : en
Pages : 1052
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Book Description
Author: Tribikram Kundu
Publisher: John Wiley & Sons
ISBN: 1118614895
Category : Technology & Engineering
Languages : en
Pages : 322
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Book Description
Ultrasonic signals are increasingly being used for predicting material behavior, both in an engineering context (detecting anomalies in a variety of structures) and a biological context (examining human bones, body parts and unborn fetuses). Featuring contributions from authors who are specialists in their subject area, this book presents new developments in ultrasonic research in both these areas, including ultrasonic NDE and other areas which go beyond traditional imaging techniques of internal defects. As such, both those in the biological and physical science communities will find this an informative and stimulating read.
Author: Akhtar S. Khan
Publisher:
ISBN:
Category : Deformations (Mechanics)
Languages : en
Pages : 698
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Book Description
Author: Ergin Alisar Tuncer
Publisher:
ISBN:
Category : Aniostropy
Languages : en
Pages : 69
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Book Description
Anisotropy and texture plays an important role in deformation of Aluminum alloy sheets. The development of anisotropy during metal forming is a key factor as in the standard industrial use of AA-6022 as stamped automotive body enclosures where a close estimation of anisotropy can deduct costs on both machinery and inventory. In this thesis, we provide a methodology to predict the anisotropic behavior of polycrystalline metals depending on its processing history. The methodology suggested is based on single crystal plasticity model of Cuitino and Ortiz where the mechanics of dislocation motion through forest dislocations is estimated statistically. In that context, we first study the role of uncertainties and responses of the initial parameters such as initial yield stress and dislocation density. R-values, which is a measure of anisotropy, of a sample undergone hydraulic bulge test are obtained by a uniaxial tensile test simulation and found to be in good agreement with the experimental findings. An optimization method to capture the texture while reducing the number of orientations is introduced and compared with random sets of orientations. Gradual work hardening effect is captured by adjusting the dislocation density carried over through consecutive simulations of rolling and uniaxial stretching. However more accurate models of rolling simulations is necessary to provide r-values and work hardening effect without the need of texture.
