Numerically Efficient Gradient Crystal Plasticity with a Grain Boundary Yield Criterion and Dislocation-based Work-Hardening
Numerically Efficient Gradient Crystal Plasticity with a Grain Boundary Yield Criterion and Dislocation-based Work-Hardening

Author: Wulfinghoff, Stephan

Publisher: KIT Scientific Publishing

Published: 2014-12-10

Total Pages: 288

ISBN-13: 3731502453

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This book is a contribution to the further development of gradient plasticity. Several open questions are addressed, where the efficient numerical implementation is particularly focused on. Thebook inspects an equivalent plastic strain gradient plasticity theory and a grain boundary yield model. Experiments can successfully be reproduced. The hardening model is based on dislocation densities evolving according to partial differential equations taking into account dislocation transport.

Single-crystal Gradient Plasticity with an Accumulated Plastic Slip: Theory and Applications
Single-crystal Gradient Plasticity with an Accumulated Plastic Slip: Theory and Applications

Author: Eric Bayerschen

Publisher: KIT Scientific Publishing

Published: 2016

Total Pages: 278

ISBN-13: 3731506068

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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.

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

Published: 2020-09-15

Total Pages: 182

ISBN-13: 3731510251

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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.

Numerically Efficient Gradient Crystal Plasticity With a Grain Boundary Yield Criterion and Dislocation-based Work-Hardening
Numerically Efficient Gradient Crystal Plasticity With a Grain Boundary Yield Criterion and Dislocation-based Work-Hardening

Author: Stephan Wulfinghoff

Publisher:

Published: 2020-10-09

Total Pages: 282

ISBN-13: 9781013280351

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This book is a contribution to the further development of gradient plasticity. Several open questions are addressed, where the efficient numerical implementation is particularly focused on. Thebook inspects an equivalent plastic strain gradient plasticity theory and a grain boundary yield model. Experiments can successfully be reproduced. The hardening model is based on dislocation densities evolving according to partial differential equations taking into account dislocation transport. 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.

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

Published: 2019-05-22

Total Pages: 222

ISBN-13: 3731509180

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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.

Work-hardening of dual-phase steel
Work-hardening of dual-phase steel

Author: Rieger, Florian

Publisher: KIT Scientific Publishing

Published: 2016-07-01

Total Pages: 202

ISBN-13: 3731505134

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Dual-phase steels exhibit good mechanical properties due to a microstructure of strong martensitic inclusions embedded in a ductile ferritic matrix. This work presents a two-scale model for the underlying work-hardening effects; such as the distinctly different hardening rates observed for high-strength dual-phase steels. The model is based on geometrically necessary dislocations and comprises the average microstructural morphology as well as a direct interaction between the constituents.

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

Published: 2023-08-25

Total Pages: 326

ISBN-13: 3731512785

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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.

Biaxial Characterization and Mean-field Based Damage Modeling of Sheet Molding Compound Composites
Biaxial Characterization and Mean-field Based Damage Modeling of Sheet Molding Compound Composites

Author: Schemmann, Malte

Publisher: KIT Scientific Publishing

Published: 2018-11-09

Total Pages: 194

ISBN-13: 3731508184

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The focus of this work lies on the microstructure-based modeling and characterization of a discontinuous fiber-reinforced thermoset in the form of sheet molding compound (SMC). A microstructure-based parameter identification scheme for SMC with an inhomogeneous fiber orientation distribution is introduced. Different cruciform specimen designs, including two concepts to reinforce the specimens' arms are evaluated. Additionally, a micromechanical mean-field damage model for the SMC is introduced.

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

Author: Lobos Fernández, Mauricio

Publisher: KIT Scientific Publishing

Published: 2018-07-09

Total Pages: 224

ISBN-13: 3731507706

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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.

Two-Scale Thermomechanical Simulation of Hot Stamping
Two-Scale Thermomechanical Simulation of Hot Stamping

Author: Neumann, Rudolf

Publisher: KIT Scientific Publishing

Published: 2017-10-27

Total Pages: 270

ISBN-13: 3731507145

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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.