Microstructural Modeling and Computational Homogenization of the Physically Linear and Nonlinear Constitutive Behavior of Micro-heterogeneous Materials

Microstructural Modeling and Computational Homogenization of the Physically Linear and Nonlinear Constitutive Behavior of Micro-heterogeneous Materials PDF Author: Felix Fritzen
Publisher: KIT Scientific Publishing
ISBN: 3866446993
Category : Technology & Engineering
Languages : en
Pages : 190

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Book Description
Engineering materials show a pronounced heterogeneity on a smaller scale that influences the macroscopic constitutive behavior. Algorithms for the periodic discretization of microstructures are presented. These are used within the Nonuniform Transformation Field Analysis (NTFA) which is an order reduction based nonlinear homogenization method with micro-mechanical background. Theoretical and numerical aspects of the method are discussed and its computational efficiency is validated.

Microstructural Modeling and Computational Homogenization of the Physically Linear and Nonlinear Constitutive Behavior of Micro-heterogeneous Materials

Microstructural Modeling and Computational Homogenization of the Physically Linear and Nonlinear Constitutive Behavior of Micro-heterogeneous Materials PDF Author: Felix Fritzen
Publisher: KIT Scientific Publishing
ISBN: 3866446993
Category : Technology & Engineering
Languages : en
Pages : 190

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Book Description
Engineering materials show a pronounced heterogeneity on a smaller scale that influences the macroscopic constitutive behavior. Algorithms for the periodic discretization of microstructures are presented. These are used within the Nonuniform Transformation Field Analysis (NTFA) which is an order reduction based nonlinear homogenization method with micro-mechanical background. Theoretical and numerical aspects of the method are discussed and its computational efficiency is validated.

Microstructure generation and micromechanical modeling of sheet molding compound composites

Microstructure generation and micromechanical modeling of sheet molding compound composites PDF Author: Görthofer, Johannes
Publisher: KIT Scientific Publishing
ISBN: 373151205X
Category : Technology & Engineering
Languages : en
Pages : 258

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Book Description
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.

Efficient fast Fourier transform-based solvers for computing the thermomechanical behavior of applied materials

Efficient fast Fourier transform-based solvers for computing the thermomechanical behavior of applied materials PDF Author: Wicht, Daniel
Publisher: KIT Scientific Publishing
ISBN: 3731512203
Category : Science
Languages : en
Pages : 336

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Book Description
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.

Modeling of Dislocation - Grain Boundary Interactions in Gradient Crystal Plasticity Theories

Modeling of Dislocation - Grain Boundary Interactions in Gradient Crystal Plasticity Theories PDF Author: Erdle, Hannes
Publisher: KIT Scientific Publishing
ISBN: 3731511967
Category : Technology & Engineering
Languages : en
Pages : 184

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Book Description
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.

Modeling martensitic phase transformation in dual phase steels based on a sharp interface theory

Modeling martensitic phase transformation in dual phase steels based on a sharp interface theory PDF Author: Ruck, Johannes
Publisher: KIT Scientific Publishing
ISBN: 3731510723
Category : Technology & Engineering
Languages : en
Pages : 220

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Book Description
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.

Two-Scale Thermomechanical Simulation of Hot Stamping

Two-Scale Thermomechanical Simulation of Hot Stamping PDF Author: Neumann, Rudolf
Publisher: KIT Scientific Publishing
ISBN: 3731507145
Category : Technology (General)
Languages : en
Pages : 270

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Book Description
Hot stamping is a hot drawing process which takes advantage of the polymorphic steel behavior to produce parts with a good strength-to-weight ratio. For the simulation of the hot stamping process, a nonlinear two-scale thermomechanical model is suggested and implemented into the FE tool ABAQUS. Phase transformation and transformation induced plasticity effects are taken into account. The simulation results regarding the final shape and residual stresses are compared to experimental findings.

Homogenization of the Linear and Non-linear Mechanical Behavior of Polycrystals

Homogenization of the Linear and Non-linear Mechanical Behavior of Polycrystals PDF Author: Katja Jöchen
Publisher: KIT Scientific Publishing
ISBN: 3866449712
Category : Science
Languages : en
Pages : 216

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Book Description
This work is dedicated to the numerically efficient simulation of the material response of polycrystalline aggregates. Therefore, crystal plasticity is combined with a new non-linear homogenization scheme, which is based on piecewise constant stress polarizations with respect to a homogeneous reference medium and corresponds to a generalization of the Hashin-Shtrikman scheme. This mean field approach accounts for the one- and two-point statistics of the microstructure.

Micromechanical Finite Element Simulations of Crack Propagation in Silicon Nitride

Micromechanical Finite Element Simulations of Crack Propagation in Silicon Nitride PDF Author: Johannes Wippler
Publisher: KIT Scientific Publishing
ISBN: 386644818X
Category : Technology & Engineering
Languages : en
Pages : 164

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Book Description
Silicon nitride is used for challening applications like cutting inserts or forming rolls. The extreme strength and toughness of the material is achieved by an interaction between the microstructure and fracture behaviour on the microlevel. In order to understand these mechanisms, detailed unit cells have been defined and used for the determination of the effective fracture properties. The results have been used for the implementation of an effective continuum damage mechanics model.

Homogenization and materials design of mechanical properties of textured materials based on zeroth-, first- and second-order bounds of linear behavior

Homogenization and materials design of mechanical properties of textured materials based on zeroth-, first- and second-order bounds of linear behavior PDF Author: Lobos Fernández, Mauricio
Publisher: KIT Scientific Publishing
ISBN: 3731507706
Category : Materials
Languages : en
Pages : 224

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Book Description
This work approaches the fields of homogenization and of materials design for the linear and nonlinear mechanical properties with prescribed properties-profile. The set of achievable properties is bounded by the zeroth-order bounds (which are material specific), the first-order bounds (containing volume fractions of the phases) and the second-order Hashin-Shtrikman bounds with eigenfields in terms of tensorial texture coefficients for arbitrarily anisotropic textured materials.

Fiber Orientation Tensors and Mean Field Homogenization: Application to Sheet Molding Compound

Fiber Orientation Tensors and Mean Field Homogenization: Application to Sheet Molding Compound PDF Author: Bauer, Julian Karl
Publisher: KIT Scientific Publishing
ISBN: 3731512629
Category : Technology & Engineering
Languages : en
Pages : 252

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Book Description
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.