Download or read book Micromechanical Finite Element Simulations of Crack Propagation in Silicon Nitride written by Johannes Wippler and published by KIT Scientific Publishing. This book was released on 2014-07-28 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Micromechanical Finite Element Simulations of Crack Propagation in Silicon Nitride written by Johannes Wippler and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Finite element simulation of dislocation based plasticity and diffusion in multiphase materials at high temperature written by Albiez, Jürgen and published by KIT Scientific Publishing. This book was released on 2019-05-22 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Micromechanical Modeling and Simulation of Forming Processes written by Glavas, Vedran and published by KIT Scientific Publishing. This book was released on 2016-12-21 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: The deep drawing of an aluminum alloy used in the packaging industry for the beverage can manufacturing process is investigated. In this work, the effective constitutive behavior is based on a crystal plasticity model in combination with a non-linear Hashin-Shtrikman type homogenization scheme in which a reference stiffness controls the stress and strain fluctuations. The simulation results are compared to experiments in terms of deep drawing earing profiles, texture evolution, and localization.
Download or read book Micromechanical modeling of short fiber reinforced composites written by Mueller, Viktor and published by KIT Scientific Publishing. This book was released on 2016-06-16 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work is focused on the prediction of elastic behavior of short-fiber reinforced composites by mean-field homogenization methods, which account for experimentally determined and artificially constructed microstructure data in discrete and averaged form. The predictions are compared with experimental measurements and a full-field voxel-based approach. It is investigated, whether the second-order orientation tensor delivers a sufficient microstructure description for such predictions.
Download or read book Microstructure generation and micromechanical modeling of sheet molding compound composites written by Görthofer, Johannes and published by KIT Scientific Publishing. This book was released on 2022-09-13 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Deep material networks for efficient scale bridging in thermomechanical simulations of solids written by Gajek, Sebastian and published by KIT Scientific Publishing. This book was released on 2023-08-25 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Two Scale Thermomechanical Simulation of Hot Stamping written by Neumann, Rudolf and published by KIT Scientific Publishing. This book was released on 2017-10-27 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Microstructure modeling and crystal plasticity parameter identification for predicting the cyclic mechanical behavior of polycrystalline metals written by Kuhn, Jannick and published by KIT Scientific Publishing. This book was released on 2023-04-04 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Thermomechanical Modeling and Experimental Characterization of Sheet Molding Compound Composites written by Lang, Juliane and published by KIT Scientific Publishing. This book was released on 2023-06-28 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Biaxial Characterization and Mean field Based Damage Modeling of Sheet Molding Compound Composites written by Schemmann, Malte and published by KIT Scientific Publishing. This book was released on 2018-11-09 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thermomechanical Mean Field Modeling and Experimental Characterization of Long Fiber Reinforced Sheet Molding Compound Composites written by Kehrer, Maria Loredana and published by KIT Scientific Publishing. This book was released on 2019-06-13 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: A discontinuous fiber-reinforced thermoset material produced by the Sheet Molding Compound process is investigated. Due to the process-related fiber orientation distribution, a composite with an anisotropic microstructure is created which crucially affects the mechanical properties. The central objectives are the modeling of the thermoelastic behavior of the composite accounting for the underlying microstructure, and the experimental characterization of the pure resin and the composite material.
Download or read book Homogenization and materials design of mechanical properties of textured materials based on zeroth first and second order bounds of linear behavior written by Lobos Fernández, Mauricio and published by KIT Scientific Publishing. This book was released on 2018-07-09 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Single crystal Gradient Plasticity with an Accumulated Plastic Slip Theory and Applications written by Eric Bayerschen and published by KIT Scientific Publishing. This book was released on 2016 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Work hardening of dual phase steel written by Rieger, Florian and published by KIT Scientific Publishing. This book was released on 2016-07-01 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book A computational multi scale approach for brittle materials written by Ernesti, Felix and published by KIT Scientific Publishing. This book was released on 2023-04-17 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Homogenization of the Linear and Non linear Mechanical Behavior of Polycrystals written by Katja Jöchen and published by KIT Scientific Publishing. This book was released on 2014-05-13 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
