Finite element simulation of dislocation based plasticity and diffusion in multiphase materials at high temperature

Finite element simulation of dislocation based plasticity and diffusion in multiphase materials at high temperature
Author: Albiez, Jürgen
Publisher: KIT Scientific Publishing
Total Pages: 222
Release: 2019-05-22
Genre: Technology & Engineering
ISBN: 3731509180

A single-crystal plasticity model as well as a gradient crystal plasticity model are used to describe the creep behavior of directionally solidi?ed NiAl based eutectic alloys. To consider the transition from theoretical to bulk strength, a hardening model was introduced to describe the strength of the reinforcing phases. Moreover, to account for microstructural changes due to material ?ux, a coupled diffusional-mechanical simulation model was introduced.

Finite Element Simulation of Dislocation Based Plasticity and Diffusion in Multiphase Materials at High Temperature

Finite Element Simulation of Dislocation Based Plasticity and Diffusion in Multiphase Materials at High Temperature
Author: Jürgen Albiez
Publisher:
Total Pages: 214
Release: 2020-10-09
Genre: Technology & Engineering
ISBN: 9781013282959

A single-crystal plasticity model as well as a gradient crystal plasticity model are used to describe the creep behavior of directionally solidi?ed NiAl based eutectic alloys. To consider the transition from theoretical to bulk strength, a hardening model was introduced to describe the strength of the reinforcing phases. Moreover, to account for microstructural changes due to material ?ux, a coupled diffusional-mechanical simulation model was introduced. This work was published by Saint Philip Street Press pursuant to a Creative Commons license permitting commercial use. All rights not granted by the work's license are retained by the author or authors.

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

Modeling of Dislocation - Grain Boundary Interactions in Gradient Crystal Plasticity Theories
Author: Erdle, Hannes
Publisher: KIT Scientific Publishing
Total Pages: 184
Release: 2022-07-12
Genre: Technology & Engineering
ISBN: 3731511967

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.

A Gradient Crystal Plasticity Theory Based on an Extended Energy Balance

A Gradient Crystal Plasticity Theory Based on an Extended Energy Balance
Author: Prahs, Andreas
Publisher: KIT Scientific Publishing
Total Pages: 182
Release: 2020-09-15
Genre: Technology & Engineering
ISBN: 3731510251

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.

Microstructure modeling and crystal plasticity parameter identification for predicting the cyclic mechanical behavior of polycrystalline metals

Microstructure modeling and crystal plasticity parameter identification for predicting the cyclic mechanical behavior of polycrystalline metals
Author: Kuhn, Jannick
Publisher: KIT Scientific Publishing
Total Pages: 224
Release: 2023-04-04
Genre: Technology & Engineering
ISBN: 3731512726

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.

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
Author: Ruck, Johannes
Publisher: KIT Scientific Publishing
Total Pages: 220
Release: 2021-05-07
Genre: Technology & Engineering
ISBN: 3731510723

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.

Deep material networks for efficient scale-bridging in thermomechanical simulations of solids

Deep material networks for efficient scale-bridging in thermomechanical simulations of solids
Author: Gajek, Sebastian
Publisher: KIT Scientific Publishing
Total Pages: 326
Release: 2023-08-25
Genre:
ISBN: 3731512785

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.

A computational multi-scale approach for brittle materials

A computational multi-scale approach for brittle materials
Author: Ernesti, Felix
Publisher: KIT Scientific Publishing
Total Pages: 264
Release: 2023-04-17
Genre: Technology & Engineering
ISBN: 3731512858

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.

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
Author: Wicht, Daniel
Publisher: KIT Scientific Publishing
Total Pages: 336
Release: 2022-10-11
Genre: Science
ISBN: 3731512203

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.