Multiscale Modeling using Molecular Dynamics and Dual Domain Material Point Method
Abstract
For problems involving large material deformation rate, the material deformation time scale can be shorter than the material takes to reach a thermodynamical equilibrium. For such problems, it is difficult to obtain a constitutive relation. History dependency become important because of thermodynamic nonequilibrium. Our goal is to build a multiscale numerical method which can bypass the need for a constitutive relation. In conclusion, multiscale simulation method is developed based on the dual domain material point (DDMP). Molecular dynamics (MD) simulation is performed to calculate stress. Since the communication among material points is not necessary, the computation can be done embarrassingly parallel in CPUGPU platform.
 Authors:
 Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division. Fluid Dynamics and Solid Mechanics Group, T3; Rice Univ., Houston, TX (United States)
 Publication Date:
 Research Org.:
 Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
 Sponsoring Org.:
 USDOE
 OSTI Identifier:
 1261793
 Report Number(s):
 LAUR1624765
 DOE Contract Number:
 AC5206NA25396
 Resource Type:
 Technical Report
 Country of Publication:
 United States
 Language:
 English
 Subject:
 36 MATERIALS SCIENCE; material science
Citation Formats
Dhakal, Tilak Raj. Multiscale Modeling using Molecular Dynamics and Dual Domain Material Point Method. United States: N. p., 2016.
Web. doi:10.2172/1261793.
Dhakal, Tilak Raj. Multiscale Modeling using Molecular Dynamics and Dual Domain Material Point Method. United States. doi:10.2172/1261793.
Dhakal, Tilak Raj. 2016.
"Multiscale Modeling using Molecular Dynamics and Dual Domain Material Point Method". United States.
doi:10.2172/1261793. https://www.osti.gov/servlets/purl/1261793.
@article{osti_1261793,
title = {Multiscale Modeling using Molecular Dynamics and Dual Domain Material Point Method},
author = {Dhakal, Tilak Raj},
abstractNote = {For problems involving large material deformation rate, the material deformation time scale can be shorter than the material takes to reach a thermodynamical equilibrium. For such problems, it is difficult to obtain a constitutive relation. History dependency become important because of thermodynamic nonequilibrium. Our goal is to build a multiscale numerical method which can bypass the need for a constitutive relation. In conclusion, multiscale simulation method is developed based on the dual domain material point (DDMP). Molecular dynamics (MD) simulation is performed to calculate stress. Since the communication among material points is not necessary, the computation can be done embarrassingly parallel in CPUGPU platform.},
doi = {10.2172/1261793},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2016,
month = 7
}

This dissertation combines the dual domain material point method (DDMP) with molecular dynamics (MD) in an attempt to create a multiscale numerical method to simulate materials undergoing large deformations with high strain rates. In these types of problems, the material is often in a thermodynamically nonequilibrium state, and conventional constitutive relations are often not available. In this method, the closure quantities, such as stress, at each material point are calculated from a MD simulation of a group of atoms surrounding the material point. Rather than restricting the multiscale simulation in a small spatial region, such as phase interfaces, or crackmore »

Shock waves simulated using the dual domain material point method combined with molecular dynamics
Here in this work we combine the dual domain material point method with molecular dynamics in an attempt to create a multiscale numerical method to simulate materials undergoing large deformations with high strain rates. In these types of problems, the material is often in a thermodynamically nonequilibrium state, and conventional constitutive relations or equations of state are often not available. In this method, the closure quantities, such as stress, at each material point are calculated from a molecular dynamics simulation of a group of atoms surrounding the material point. Rather than restricting the multiscale simulation in a small spatial region,more » 
Gradientdriven diffusion using dual control volume grand canonical molecular dynamics
The dual control volume grand canonical molecular dynamics (DCVGCMD) method, designed to enable the dynamic simulation of a system with a steady state chemical potential gradient is first briefly reviewed. A new, novel implementation of the method which enables the establishment of a steady state chemical potential gradient in a multicomponent system without having to insert or delete one of the components is then presented and discussed.