A Gradient Crystal Plasticity Theory Based On An Extended Energy Balance

Author : Prahs, Andreas
Publisher : KIT Scientific Publishing
Page : 182 pages
File Size : 55,8 Mb
Release : 2020-09-15
Category : Technology & Engineering
ISBN : 9783731510253

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A Gradient Crystal Plasticity Theory Based on an Extended Energy Balance by Prahs, Andreas Pdf

An overview of different methods for the derivation of extended continuum models is given. A gradient plasticity theory is established in the context of small deformations and single slip by considering the invariance of an extended energy balance with respect to Euclidean transformations, where the plastic slip is considered as an additional degree of freedom. Thermodynamically consistent flow rules at the grain boundary are derived. The theory is applied to a two- and a three-phase laminate.

Author : Erdle, Hannes
Publisher : KIT Scientific Publishing
Page : 184 pages
File Size : 40,6 Mb
Release : 2022-07-12
Category : Technology & Engineering
ISBN : 9783731511960

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Modeling of Dislocation - Grain Boundary Interactions in Gradient Crystal Plasticity Theories by Erdle, Hannes Pdf

A physically-based dislocation theory of plasticity is derived within an extended continuum mechanical context. Thermodynamically consistent flow rules at the grain boundaries are derived. With an analytical solution of a three-phase periodic laminate, dislocation pile-up at grain boundaries and dislocation transmission through the grain boundaries are investigated. For the finite element implementations, numerically efficient approaches are introduced based on accumulated field variables.

Author : Kuhn, Jannick
Publisher : KIT Scientific Publishing
Page : 224 pages
File Size : 47,9 Mb
Release : 2023-04-04
Category : Technology & Engineering
ISBN : 9783731512721

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Microstructure modeling and crystal plasticity parameter identification for predicting the cyclic mechanical behavior of polycrystalline metals by Kuhn, Jannick Pdf

Computational homogenization permits to capture the influence of the microstructure on the cyclic mechanical behavior of polycrystalline metals. In this work we investigate methods to compute Laguerre tessellations as computational cells of polycrystalline microstructures, propose a new method to assign crystallographic orientations to the Laguerre cells and use Bayesian optimization to find suitable parameters for the underlying micromechanical model from macroscopic experiments.

Author : Wicht, Daniel
Publisher : KIT Scientific Publishing
Page : 336 pages
File Size : 42,7 Mb
Release : 2022-10-11
Category : Science
ISBN : 9783731512202

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Efficient fast Fourier transform-based solvers for computing the thermomechanical behavior of applied materials by Wicht, Daniel Pdf

The mechanical behavior of many applied materials arises from their microstructure. Thus, to aid the design, development and industrialization of new materials, robust computational homogenization methods are indispensable. The present thesis is devoted to investigating and developing FFT-based micromechanics solvers for efficiently computing the (thermo)mechanical response of nonlinear composite materials with complex microstructures.

Author : Lang, Juliane
Publisher : KIT Scientific Publishing
Page : 250 pages
File Size : 43,6 Mb
Release : 2023-06-28
Category : Electronic
ISBN : 9783731512325

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Thermomechanical Modeling and Experimental Characterization of Sheet Molding Compound Composites by Lang, Juliane Pdf

The aim of this work is to model and experimentally characterize the anisotropic material behavior of SMC composites on the macroscale with consideration of the microstructure. Temperature-dependent thermoelastic behavior and failure behavior are modeled and the corresponding material properties are determined experimentally. Additionally, experimental biaxial damage investigations are performed. A parameter identification merges modeling and experiments and validates the models.

Author : Ernesti, Felix
Publisher : KIT Scientific Publishing
Page : 264 pages
File Size : 42,5 Mb
Release : 2023-04-17
Category : Technology & Engineering
ISBN : 9783731512851

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A computational multi-scale approach for brittle materials by Ernesti, Felix Pdf

Materials of industrial interest often show a complex microstructure which directly influences their macroscopic material behavior. For simulations on the component scale, multi-scale methods may exploit this microstructural information. This work is devoted to a multi-scale approach for brittle materials. Based on a homogenization result for free discontinuity problems, we present FFT-based methods to compute the effective crack energy of heterogeneous materials with complex microstructures.

Author : Gajek, Sebastian
Publisher : KIT Scientific Publishing
Page : 326 pages
File Size : 47,6 Mb
Release : 2023-08-25
Category : Electronic
ISBN : 9783731512783

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Deep material networks for efficient scale-bridging in thermomechanical simulations of solids by Gajek, Sebastian Pdf

We investigate deep material networks (DMN). We lay the mathematical foundation of DMNs and present a novel DMN formulation, which is characterized by a reduced number of degrees of freedom. We present a efficient solution technique for nonlinear DMNs to accelerate complex two-scale simulations with minimal computational effort. A new interpolation technique is presented enabling the consideration of fluctuating microstructure characteristics in macroscopic simulations.

Author : Görthofer, Johannes
Publisher : KIT Scientific Publishing
Page : 258 pages
File Size : 44,8 Mb
Release : 2022-09-13
Category : Technology & Engineering
ISBN : 9783731512059

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Microstructure generation and micromechanical modeling of sheet molding compound composites by Görthofer, Johannes Pdf

Wir präsentieren einen Algorithmus zur schnellen Erzeugung von SMC Mikrostrukturen hoher Güte, durch Verwendung einer exakten Schließung und eines quasi-zufälligen Samplings. Darüber hinaus stellen wir ein modulares Framework zur Modellierung anisotroper Schädigung vor. Unser Konzept der Extraktionstensoren und Schädigungsfunktionen ermöglicht die Beschreibung komplexer Vorgänge. Darüber hinaus schlagen wir einen ganzheitlichen Multiskalenansatz zur Bestimmung anisotroper Versagenskriterien vor. - We introduce an algorithm that allows for a fast generation of SMC composite microstructures. An exact closure approximation and a quasi-random orientation sampling ensure high fidelity. Furthermore, we present a modular framework for anisotropic damage evolution. Our concept of extraction tensors and damage-hardening functions enables the description of complex damage-degradation. In addition, we propose a holistic multiscale approach for constructing anisotropic failure criteria.

Author : Bauer, Julian Karl
Publisher : KIT Scientific Publishing
Page : 252 pages
File Size : 44,7 Mb
Release : 2023-02-27
Category : Technology & Engineering
ISBN : 9783731512622

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Fiber Orientation Tensors and Mean Field Homogenization: Application to Sheet Molding Compound by Bauer, Julian Karl Pdf

Effective mechanical properties of fiber-reinforced composites strongly depend on the microstructure, including the fibers' orientation. Studying this dependency, we identify the variety of fiber orientation tensors up to fourth-order using irreducible tensors and material symmetry. The case of planar fiber orientation tensors, relevant for sheet molding compound, is presented completely. Consequences for the reconstruction of fiber distributions and mean field homogenization are presented.

Author : Ruck, Johannes
Publisher : KIT Scientific Publishing
Page : 220 pages
File Size : 51,6 Mb
Release : 2021-05-07
Category : Technology & Engineering
ISBN : 9783731510727

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Modeling martensitic phase transformation in dual phase steels based on a sharp interface theory by Ruck, Johannes Pdf

artensite forms under rapid cooling of austenitic grains accompanied by a change of the crystal lattice. Large deformations are induced which lead to plastic dislocations. In this work a transformation model based on the sharp interface theory, set in a finite strain context is developed. Crystal plasticity effects, the kinetic of the singular surface as well as a simple model of the inheritance from austenite dislocations into martensite are accounted for.

Author : Bernd Markert
Publisher : Springer Science & Business Media
Page : 231 pages
File Size : 51,6 Mb
Release : 2011-07-15
Category : Science
ISBN : 9783642227387

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Advances in Extended and Multifield Theories for Continua by Bernd Markert Pdf

Modern computational techniques, such as the Finite Element Method, have, since their development several decades ago, successfully exploited continuum theories for numerous applications in science and technology. Although standard continuum methods based upon the Cauchy-Boltzmann continuum are still of great importance and are widely used, it increasingly appears that material properties stemming from microstructural phenomena have to be considered. This is particularly true for inhomogeneous load and deformation states, where lower-scale size effects begin to affect the macroscopic material response; something standard continuum theories fail to account for. Following this idea, it is evident that standard continuum mechanics has to be augmented to capture lower-scale structural and compositional phenomena, and to make this information accessible to macroscopic numerical simulations.

Author : Wulfinghoff, Stephan
Publisher : KIT Scientific Publishing
Page : 290 pages
File Size : 50,7 Mb
Release : 2014-12-10
Category : Electronic
ISBN : 9783731502456

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Numerically Efficient Gradient Crystal Plasticity with a Grain Boundary Yield Criterion and Dislocation-based Work-Hardening by Wulfinghoff, Stephan Pdf

Author : Carlo Sansour,Sebastian Skatulla
Publisher : Springer Science & Business Media
Page : 323 pages
File Size : 42,8 Mb
Release : 2012-05-27
Category : Science
ISBN : 9783709112229

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Generalized Continua and Dislocation Theory by Carlo Sansour,Sebastian Skatulla Pdf

Defects, dislocations and the general theory.- Approaches to generalized continua.- Generalized continuum modelling of crystal plasticity.- Introduction to discrete dislocation dynamics. The book contains four lectures on generalized continua and dislocation theory, reflecting the treatment of the subject at different scales. G. Maugin provides a continuum formulation of defects at the heart of which lies the notion of the material configuration and the material driving forces of in-homogeneities such as dislocations, disclinations, point defects, cracks, phase-transition fronts and shock waves. C. Sansour and S. Skatulla start with a compact treatment of linear transformation groups with subsequent excursion into the continuum theory of generalized continua. After a critical assessment a unified framework of the same is presented. The next contribution by S. Forest gives an account on generalized crystal plasticity. Finally, H. Zbib provides an account of dislocation dynamics and illustrates its fundamental importance at the smallest scale. In three contributions extensive computational results of many examples are presented.

Author : Eric Bayerschen
Publisher : KIT Scientific Publishing
Page : 278 pages
File Size : 45,6 Mb
Release : 2016-12-29
Category : Electronic
ISBN : 9783731506065

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Single-crystal Gradient Plasticity with an Accumulated Plastic Slip: Theory and Applications by Eric Bayerschen Pdf

Author : Paul Steinmann
Publisher : Springer Science & Business Media
Page : 271 pages
File Size : 52,9 Mb
Release : 2009-08-03
Category : Science
ISBN : 9789048134472

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IUTAM Symposium on Progress in the Theory and Numerics of Configurational Mechanics by Paul Steinmann Pdf

Con?gurational mechanics has attracted quite a bit of attention from various - search ?elds over the recent years/decades. Having been regarded in its infancy of the early years as a somewhat obscureand almost mystic ?eld of researchthat could only be understood by a happy few of insiders with a pronounced theoretical inc- nation, con?gurational mechanics has developed by now into a versatile tool that can be applied to a variety of problems. Since the seminal works of Eshelby a general notion of con?gurational - chanics has been developed and has successfully been applied to many pr- lems involving various types of defects in continuous media. The most pro- nent application is certainly the use of con?gurational forces in fracture - chanics. However, as con?gurational mechanics is related to arbitrary mat- ial inhomogeneities it has also very successfully been applied to many ma- rials science and engineering problems such as phase transitions and inelastic deformations. Also the modeling of materials with micro-structure evolution is an important ?eld, in which con?gurational mechanics can provide a better understanding of processes going on within the material. Besides these mechanically, physically, and chemically motivated applications, ideas from con?gurational mechanics are now increasingly applied within computational mechanics.