Multiscale Modeling Group
Welcome to the Multiscale Modeling Group. We aim to design high-throughput process models for advanced manufacturing of metal-based alloys and nanocomposites. Our models cover a wide range of length- and time-scales while being developed and tested with commercial and open-source software on various computing infrastructures from regular workstations to supercomputers. Through close internal and external collaborations, we also carry out our benchmark and validation experiments as well as advanced statistical analysis and machine learning. Currently, we are pursuing two main research directions (RDs) as defined below.
RD1: Developing multi-physics models for metal 3D printing
Our approach
We adopt the Eulerian-Lagrangian framework to numerically describe the multiphysics nature of metal 3D printing. We use
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Computational Fluid Dynamics (CFD) based on Finite Volume Method (FVM) to model heat and mass transport in each phase as well as solid-liquid phase transitions in the substrate
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Volume-of-Fluid (VOF) method to model solid-gas and liquid-gas interfaces, involving multiphase flow
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Discrete Element Method (DEM) to model powder particles and laser photons and their interactions
We develop and apply customized subroutines for the CFD-DEM-VOF coupling to describe particle-fluid and particle-interface interactions, also including laser-matter interactions.
Our tools
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OpenFOAM - open-source FVM-based software designed for CFD simulations
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Aspherix - commercial DEM software designed for modeling granular media
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CFDEM coupling - commercial software designed for modeling particle-fluid interactions with partially open code allowing for customized subroutines for CFD-DEM coupling using OpenFOAM and Aspherix
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ParaView - open-source software used for post-processing and visualization of simulation results from software listed above
Representative publications
RD2: Employing atomistic simulations and ab initio calculations for nanoscale materials design
We adopt major open-source community codes for atomistic simulations and quantum calculations to access various processes and properties of materials at the nanoscale. We rely on well-established theories and phenomenological modeling to analyze and interpret our modeling results as well as guide the development of new theories and mesoscale modeling tools.
Our tools
- LAMMPS - a high-performance atomistic modeling code enabling large-scale atomistic simulations with millions or even billions of atoms
- Quantum ESPRESSO -an integrated suite of open-source codes for electronic-structure calculations and materials modeling at the nanoscale based on density-functional theory, plane waves, and pseudopotentials
- CP2K - a quantum chemistry and solid state physics software package providing a general framework for different modeling methods such as DFT using the mixed Gaussian and plane waves approaches
- OVITO - a visualization and analysis software for output data generated in molecular dynamics, atomistic Monte-Carlo and other particle-based simulations (partially commercial, premium licenses available in the group)
Representative publications:
Atomistic Simulations of the Crystalline-to-Amorphous Transformation of γ-Al2O3 Nanoparticles: Delicate Interplay between Lattice Distortions, Stresses, and Space Charge, Langmuir (2023) Atomistic Assessment of Melting Point Depression and Enhanced Interfacial Diffusion of Cu in Confinement with AlN, ACS Applied Materials & Interfaces (2022) Prediction of a wide variety of linear complexions in face centered cubic alloys, Acta Materialia (2020) - Grain boundary complexions and the strength of nanocrystalline metals: Dislocation emission and propagation, Acta Materialia (2018)
- Modeling self-sustaining waves of exothermic dissolution in nanometric Ni-Al multilayers, Acta Materialia (2016)
TEAM PHOTOS
The first generation (2020-2022) - August 2022 - Thun
Team leader
Expert in large-scale atomistic simulations
Scientists
Dr. Manura Liyanage
Expert in machine learning interatomic potential (MLIP) development
Project: Large-scale atomistic modeling of Cu/W interfaces
Guest scientists
Dr. Terrence Moran
Expert in metal 3D printing
Project: 3D printing of nanoparticle-reinforced Ti matrix composites
Ph.D. students
Project: Atomistic modeling of systems with complex chemical bonding
Finished projects and alumni
Postdoctoral projects
- Dr. Giandomenico Lupo (2020-2022): Multiphysics modeling of laser-matter interactions
- Dr. Javier Fernandez Troncoso (2021-2022): Ab initio modeling of Cu/W interfaces
- Dr. Javier Fernandez Troncoso (2020-2021): Atomistic modeling and machine learning for Mg research
PhD-related projects
- Simon Gramatte (2020-2021): Atomistic study of solid/liquid interface mobility
Master theses
- Yann Muller (2021): Molecular dynamics simulations of Cu/AlN nano-multilayers
Internships
- Stefan Scharen (2022): Atomistic simulations of heterogeneous nucleation
- Yann Muller (2022): Ab initio modeling of Cu/AlN nano-multilayers
- Stephane Nilsson (2021): Bayesian inference for multiphysics models of laser melting
- Daniele Hamm (2021): Bayesian inference for heat transfer models of laser melting
- Jose Simon Greminger (2021): Atomistic modeling of heterogeneous nucleation
- Jose Simon Greminger (2020): Atomistic modeling of alumina nanoparticles