Molecular dynamics-guided material model for the simulation of shock-induced pore collapse in β-octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (β-HMX)

2021 ◽  
Vol 130 (8) ◽  
pp. 085901 ◽  
Author(s):  
Pratik Das ◽  
Puhan Zhao ◽  
Dilki Perera ◽  
Tommy Sewell ◽  
H. S. Udaykumar
Keyword(s):  
Molecular Dynamics ◽  
Material Model ◽  
Pore Collapse

scholarly journals Characterization of polystyrene under shear deformation using Molecular Dynamics

2021 ◽  
Author(s):  
Maximilian Ries ◽  
Paul Steinmann ◽  
Sebastian Pfaller
Keyword(s):  
Molecular Dynamics ◽  
Shear Deformation ◽  
Pure Shear ◽  
Material Model ◽  
Md Simulations ◽  
Constitutive Law ◽  
Coupling Scheme ◽  
Suitable Material ◽  
Continuum Description ◽  
The Continuum

Nano-filled polymers are becoming more and more important to meet the continuously growing requirements of modern engineering problems. The investigation of these composite materials at the molecular level, however, is either prohibitively expensive or just impossible. Multiscale approaches offer an elegant way to analyze such nanocomposites by significantly reducing computational costs compared to fully molecular simulations.When coupling different time and length scales, however, it is in particular important to ensure that the same material description is applied at each level of resolution.The Capriccio method, for instance, couples a particle domain modeled with molecular dynamics (MD) with a finite element based continuum description and has been used i.a. to investigate the effects of nano-sized silica additives embedded in atactic polystyrene (PS). However, a simple hyperelastic constitutive law is used so far for the continuum description which is not capable to fully match the behavior of the particle domain. To overcome this issue and to enable further optimization of the coupling scheme, the material model used for the continuum should be derived directly from pure MD simulations under thermodynamic conditions identical to those used by the Capriccio method.To this end, we analyze the material response of pure PS under uniaxial deformation using strain-controlled MD simulations. Analogously, we perform simulations under pure shear deformation to obtain a comprehensive understanding of the material behavior.As a result, the present PS shows viscoelastic characteristics for small strains, whereas viscoplasticity is observed for larger deformations. The insights gained and data generated are used to select a suitable material model whose parameters have to be identified in a subsequent parameter optimization.

scholarly journals Особенности воздействия ионов He и Ar низких энергий на нанопористые Si/SiO-=SUB=-2-=/SUB=--материалы

2020 ◽  
Vol 46 (11) ◽  
pp. 15
Author(s):  
А.А. Сычева ◽  
Е.Н. Воронина
Keyword(s):  
Molecular Dynamics ◽  
Structural Changes ◽  
Ion Irradiation ◽  
Nanoporous Materials ◽  
Low Energy ◽  
Pore Collapse ◽  
Surface Layers ◽  
Nanoporous Si ◽  
Dynamics Simulations ◽  
Low Energy Ions

In this paper molecular dynamics simulations of low-energy (50–200 eV) ion irradiation of nanoporous Si/SiO2-based materials were performed. Obtained results confirm the experimentally observed the densification of the uppermost surface layers of materials with small (less than 1.5 nm) pores due to pore collapse initiated by incident ions. Special features of the irradiation of nanoporous materials with He and Ar low-energy ions and the influence of their energy on structural changes of materials under study are discussed.

scholarly journals Tandem Molecular Dynamics and Continuum Studies of Shock‐Induced Pore Collapse in TATB

2020 ◽  
Vol 45 (2) ◽  
pp. 196-222 ◽  
Author(s):  
Puhan Zhao ◽  
Sangyup Lee ◽  
Tommy Sewell ◽  
H. S. Udaykumar
Keyword(s):  
Molecular Dynamics ◽  
Pore Collapse

Continuum and molecular dynamics simulations of pore collapse in shocked β-tetramethylene tetranitramine (β-HMX) single crystals

2021 ◽  
Vol 129 (1) ◽  
pp. 015904
Author(s):  
Camilo A. Duarte ◽  
Chunyu Li ◽  
Brenden W. Hamilton ◽  
Alejandro Strachan ◽  
Marisol Koslowski
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Single Crystals ◽  
Pore Collapse ◽  
Dynamics Simulations

Thermal Transport Mechanisms in Carbon Nanotube-Nanofluids Identified From Molecular Dynamics Simulations

2015 ◽  
Vol 137 (7) ◽  
Author(s):  
Jonathan W. Lee ◽  
Andrew J. Meade ◽  
Enrique V. Barrera ◽  
Jeremy A. Templeton
Keyword(s):  
Molecular Dynamics ◽  
Thermal Transport ◽  
Effective Conductivity ◽  
Low Frequency ◽  
Material Model ◽  
Nonequilibrium Molecular Dynamics ◽  
Atomistic Simulations ◽  
Liquid Environment ◽  
Dynamics Simulations ◽  
Surrounding Fluid

Atomistic simulations of carbon nanotubes (CNTs) in a liquid environment are performed to better understand thermal transport in CNT-based nanofluids. Thermal conductivity is studied using nonequilibrium molecular dynamics (MD) methods to understand the effective conductivity of a solvated CNT combined with a novel application of Hamilton–Crosser (HC) theory to estimate the conductivity of a fluid suspension of CNTs. Simulation results show how the presence of the fluid affects the CNTs ability to transport heat by disrupting the low-frequency acoustic phonons of the CNT. A spatially dependent use of the Irving–Kirkwood relations reveals the localized heat flux, illuminating the heat transfer pathways in the composite material. Model results can be consistently incorporated into HC theory by considering ensembles of CNTs and their surrounding fluid as being present in the liquid. The simulation-informed theory is shown to be consistent with existing experimental results.

scholarly journals Study on Lightweight and Strengthening Effect of Carbon Nanotube in Highly Ordered Nanoporous Nickel: A Molecular Dynamics Study

2019 ◽  
Vol 9 (2) ◽  
pp. 352 ◽  
Author(s):  
Yu Zhou ◽  
Wu-Gui Jiang ◽  
Duo-Sheng Li ◽  
Qing-Hua Qin
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Carbon Nanotube ◽  
Tensile Modulus ◽  
Md Simulations ◽  
Absorption Capacity ◽  
Atomic Scale ◽  
Strengthening Effect ◽  
Pore Collapse ◽  
Out Of Plane

The mechanical behavior of nanocomposites consisting of highly ordered nanoporous nickel (HONN) and its carbon nanotube (CNT)-reinforced composites (CNHONNs) subjected to a high temperature of 900 K is investigated via molecular dynamics (MD) simulations. The study indicates that, out-of-plane mechanical properties of the HONNs are generally superior to its in-plane mechanical properties. Whereas the CNT shows a significant strengthening effect on the out-of-plane mechanical properties of the CNHONN composites. Compared to pure HONNs, through the addition of CNTs from 1.28 wt‰ to 5.22 wt‰, the weight of the composite can be reduced by 5.83‰ to 2.33% while the tensile modulus, tensile strength, compressive modulus and compressive strength can be increased by 2.2% to 8.8%, 1% to 5.1%, 3.6% to 10.2% and 4.9% to 10.7%, respectively. The energy absorption capacity can also be improved due to the existence of CNTs. Furthermore, the MD simulations provide further insights into the deformation mechanism at the atomic scale, including fracture in tension, pore collapse in compression and local changes in lattice structures due to stacking faults.

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