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Showing 1 to 18 of 18 for “"Multiscale method"”.
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A Multiscale Method for Simulating Fracture in Polycrystalline Metals
… motivates the formulation of computational multiscale methods to link macroscopic failure to the underlying atomic processes from which all material behavior originates. A combined concurrent and sequential multiscale methodology is developed to analyze fracture mechanisms across length …
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An adaptive variational multiscale method with discontinuous subscales for aerodynamic flows
A promising methodology for accurate and efficient simulation of aerodynamic flows is output-based mesh adaptation, which optimizes a mesh to minimize the discretization error in an output of interest. The state of the art in output-based adaptation uses the discontinuous Galerkin (DG) method, …
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Variational multiscale method for coupled systems: free-surface flows and stratified turbulence
This dissertation presents a robust numerical method for the class of coupled systems comprised of multiple interacting partial differential equations (PDE). Particular emphasis is placed on incompressible Navier-Stokes equations that are coupled with a hyperbolic scalar PDE. The method is derived …
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Variational multiscale method for fluid-structure interaction on non-matching meshes and turbulent flows around immersed objects
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2022-11-11 without embargo terms
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A locally conservative variational multiscale method for the simulation of porous media flow with multiscale source terms
Multiscale phenomena are ubiquitous to flow and transport in porous media. They manifest themselves through at least the following three facets: (1) effective parameters in the governing equations are scale dependent; (2) some features of the flow (especially sharp fronts and boundary layers) …
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Multiscale modeling of rate dependence and size effects on nanocrystalline metallic thin films
… increased rate sensitivity. This work presents a multiscale finite element solver aimed at capturing the effects of grain-level deformation mechanisms and the material microstructure on the macroscopic elastic and plastic behavior of nanocrystalline thin films. The traditional multiscale method is …
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Electrostatic Analysis of Nanoelectromechanical Systems
In addition to the multiscale method, we present an ab initio study of electronic properties of graphene flakes and nanoribbons adsorbed on clean and H-passivated (100) silicon surfaces. The graphene electronic properties are not perturbed by the H-passivated Si substrate. In contrast, the …
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First principles Monte Carlo simulation of charge transport in semiconductors
A new multiscale method is presented for modeling charge transport across a semi-conductor heterointerface. It has the advantage of increase predictive power due to its treatment of the detailed mixing between Bloch and Tamm electronic states in the interface region; this is of critical importance …
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Multiscale modeling strategies for chemical vapor deposition
… we develop the overlapping computational domains method. The simulation results obtained with the multiscale method are in excellent agreement with experimental data for selective epitaxy of AlGaAs in the presence of HC1. A KMC model is developed for AlGaAs surface morphology evolution during …
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Modeling Droplet Impingement Dynamics on Micropillar-Arrayed Viscoelastic Substrates Through Microgeometry-Free and Multiscale Methods
… thoroughly investigated by two distinct modeling methods, i.e., microgeometry-free and multiscale modeling methods. The viscoelasticity of the micropillar-arrayed substrate is characterized by a five-parameter generalized Maxwell model via the Laplace-Carson transform. In the microgeometry-free …
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Multiscale Analysis of Macromolecular Systems
… understanding of macromolecular systems. A new multiscale method, Locally Scaled Diffusion Map (LSDMap), has been introduced to extract the optimal collective reaction coordinates from MD data without a priori knowledge of the system. The method decouples motions with different timescales into a …
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Non-equilibrium Thermodynamic Approach Based on the Steepest-Entropy-Ascent Framework Applicable across All Temporal and Spatial Scales
… framework across all scales, a density of states method is developed, which is applicable to solving the SEAQT equation of motion for all types of non-equilibrium relaxation processes. In addition, a heterogeneous multiscale method (HMM) algorithm is also applied to extend the application of the …
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A variational framework for multi-scale defect modeling in strained electronics and processing of composite materials
… reaction across the multi-phase interfaces. The method is based on employing structured non-moving meshes to solve the Navier-Stokes equations employing a finite element method (FEM) stabilized via the Variational Multiscale Method (VMS). Within VMS framework a discontinuity capturing method is …
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Residual-based turbulence models for incompressible flows in domains with moving boundaries
… with moving boundaries and interfaces. The method is derived employing the Variational Multiscale (VMS) framework, which gives rise to several modeling options that are exploited to obtain accurate turbulence models. To accommodate problems with moving boundaries such as fluid-structure …
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Modeling the effect of debonding on the constitutive response of heterogeneous materials
… structures are on the scale of meters, a multiscale method is necessary to accurately simulate damage and failure. This work has focused on using two homogenization approaches to investigate the relationship between microstructural damage and macroscopic constitutive response: a nonlinear …
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A unified computational framework for process modeling and performance modeling of multi-constituent materials
This Dissertation was approved for publication on 2016-09-06 at 08:58.
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A variational multiscale computational framework for reaction-dominated thermo-chemo-mechanical process modeling in multi-constituent material systems
… (i) new robust variational multi-scale numerical methods that are consistently derived, and (ii) models for multi-physics processes in multi-constituent materials. New robust numerical methods are developed via the variational multiscale (VMS) framework. Through the concept of fine scales in VMS, …
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Bridging the gap between atomistic and continuum models to predict dielectric and thermodynamic properties of confined fluids
… at atomic level. Thus, there is a need for a multiscale frame work to maintain the balance between accuracy and rigor of atomistic simulations and efficiency of continuum frameworks. In this work, we present an empirical potential-based quasi-continuum theory (EQT) that provides a framework to …