Sample Geometry and the Brittle-Ductile Behavior of Edge Cracks in 3D Atomistic Simulations by Molecular Dynamics

2016 ◽  
Vol 258 ◽  
pp. 45-48 ◽  
Author(s):  
Vladimír Pelikán ◽  
Petr Hora ◽  
Anna Machová ◽  
Radek Kolman ◽  
Alena Uhnáková
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamic ◽  
Md Simulations ◽  
Atomistic Simulations ◽  
Mode I ◽  
Sample Geometry ◽  
Bcc Iron ◽  
T Stress ◽  
Edge Cracks ◽  
Ductile Behavior

We present new results of molecular dynamic (MD) simulations in 3D bcc iron crystals with edge cracks (001)[010] and (-110)[110] loaded in mode I. Different sample geometries of SEN type were tested with negative and positive values of T-stress according to continuum prediction by Fett.

Ductile-Brittle Behavior along Crack Front and T-Stress

2011 ◽  
Vol 465 ◽  
pp. 69-72
Author(s):  
Alena Uhnáková ◽  
Anna Machová ◽  
Petr Hora
Keyword(s):  
Stress Analysis ◽  
Molecular Dynamic ◽  
Crack Front ◽  
Crystallographic Orientation ◽  
Md Simulations ◽  
Mode I ◽  
Brittle Behavior ◽  
Bcc Iron ◽  
T Stress ◽  
The Continuum

We present new results of molecular dynamic (MD) simulations in 3D bcc iron crystals with embedded central through crack (001)[110] of Griffith type loaded in mode I. Two different sample geometries of the same crystallographic orientation were tested with negative and positive values of the T-stress, which change the ductile-brittle behavior along the crack front in 3D. This phenomenon is explained in the framework of stress analysis, both on the continuum and atomistic level.

Crack Orientation versus Ductile-Brittle Behavior in 3D Atomistic Simulations

2007 ◽  
Vol 567-568 ◽  
pp. 61-64 ◽  
Author(s):  
Alena Spielmannová ◽  
Anna Machová ◽  
Petr Hora
Keyword(s):  
Room Temperature ◽  
Md Simulations ◽  
Atomistic Simulations ◽  
Mode I ◽  
Crack Plane ◽  
Crack Orientation ◽  
Brittle Behavior ◽  
Bcc Iron ◽  
Fracture Tests ◽  
Recent Fracture

The paper presents results of molecular dynamic (MD) simulations in 3D bcc iron crystals with edge pre-existing cracks (001)[110] and (110) [110] (crack plane/crack front) loaded uni-axially in tension mode I at temperature of 300 K. The iron crystals in MD have the same orientation and similar geometry as in our recent fracture tests performed at room temperature on iron (3wt.%Si) single crystals [1].

Molecular Dynamics Simulation of a Pullout Test on a Carbon Nanotube in a Polymer Matrix

2014 ◽  
Vol 1700 ◽  
pp. 61-66
Author(s):  
Guttormur Arnar Ingvason ◽  
Virginie Rollin
Keyword(s):  
Molecular Dynamics ◽  
Polymer Matrix ◽  
Large Scale ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Atomistic Simulations ◽  
Polymer Molecules ◽  
Molecular Potential ◽  
Pull Out ◽  
Walled Carbon Nanotubes

ABSTRACTAdding single walled carbon nanotubes (SWCNT) to a polymer matrix can improve the delamination properties of the composite. Due to the complexity of polymer molecules and the curing process, few 3-D Molecular Dynamics (MD) simulations of a polymer-SWCNT composite have been run. Our model runs on the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS), with a COMPASS (Condensed phase Optimized Molecular Potential for Atomistic Simulations Studies) potential. This potential includes non-bonded interactions, as well as bonds, angles and dihedrals to create a MD model for a SWCNT and EPON 862/DETDA (Diethyltoluenediamine) polymer matrix. Two simulations were performed in order to test the implementation of the COMPASS parameters. The first one was a tensile test on a SWCNT, leading to a Young’s modulus of 1.4 TPa at 300K. The second one was a pull-out test of a SWCNT from an originally uncured EPON 862/DETDA matrix.

Growth of 3D edge cracks in mode I and T-stress on the atomistic level

2017 ◽  
Vol 138 ◽  
pp. 315-322 ◽  
Author(s):  
Anna Machová ◽  
Alena Uhnáková ◽  
Petr Hora
Keyword(s):  
Mode I ◽  
T Stress ◽  
Edge Cracks

scholarly journals Molecular dynamics simulations of the self-organization of side-chain decorated polyaromatic conjugation molecules: phase separated lamellar and columnar structures and dispersion behaviors in toluene solvent

RSC Advances ◽  
2018 ◽  
Vol 8 (20) ◽  
pp. 11134-11144 ◽  
Author(s):  
Lanyan He ◽  
Pingmei Wang ◽  
Lipeng He ◽  
Zhou Qu ◽  
Jianhui Luo ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Molecular Dynamic ◽  
Md Simulations ◽  
The Self ◽  
Self Organization ◽  
Side Chain ◽  
Dynamics Simulations

The self-organization of five model side-chain decorated polyaromatic asphaltene molecules with or without toluene solvent was investigated by means of molecular dynamic (MD) simulations.

scholarly journals Stability of Two-quartet G-quadruplexes and Their Dimers in Atomistic Simulations

2019 ◽  
Author(s):  
Barira Islam ◽  
Petr Stadlbauer ◽  
Michaela Vorlíčková ◽  
Jean-Louis Mergny ◽  
Michal Otyepka ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Md Simulations ◽  
The Other ◽  
Atomistic Simulations ◽  
Structural Element ◽  
Dna And Rna ◽  
Open Issue ◽  
Water Models ◽  
Weakly Stable ◽  
The Stability

ABSTRACTG-quadruplexes (GQs) are four-stranded non-canonical DNA and RNA architectures that can be formed by guanine-rich sequences. The stability of GQs increases with the number of G-quartets and three G-quartets generally form stable GQs. However, the stability of two-quartet GQs is an open issue. To understand the intrinsic stability of two-quartet GQ stems, we have carried out a series of unbiased molecular dynamics (MD) simulations (∼505 µs in total) of two- and four-quartet DNA and RNA GQs, with attention paid mainly to parallel-stranded arrangements. We used AMBER DNA parmOL15 and RNA parmOL3 force fields and tested different ion and water models. DNA two-quartet parallel-stranded GQs unfolded in all the simulations while the equivalent RNA GQ was stable in most of the simulations. GQs composed of two stacked units of two-quartet GQs were stable for both DNA and RNA. The simulations suggest that a minimum of three quartets are needed to form an intrinsically stable all-anti parallel-stranded DNA GQ. Parallel two-quartet DNA GQ may exist if substantially stabilized by another molecule or structural element, including multimerisation. On the other hand, we predict that isolated RNA two-quartet parallel GQs may form, albeit being weakly stable. We also show that ionic parameters and water models should be chosen with caution because some parameter combinations can cause spurious instability of GQ stems. Some in-so-far unnoticed limitations of force-field description of multiple ions inside the GQs are discussed, which compromise capability of simulations to fully capture the effect of increase of the number of quartets on the GQ stability.

Ductile-Brittle Behavior of Microcracks in 3D

2005 ◽  
Vol 482 ◽  
pp. 131-134
Author(s):  
V. Pelikán ◽  
Petr Hora ◽  
Anna Machová ◽  
Michal Landa
Keyword(s):  
Molecular Dynamics ◽  
Crack Initiation ◽  
Mode I ◽  
Dislocation Emission ◽  
Brittle Behavior ◽  
Free Sample ◽  
Bcc Iron ◽  
Parallel Molecular Dynamics

Results of several parallel molecular dynamics crack simulations in bcc iron crystals with up to 128 million atoms are presented. The crack (001)[010] of Griffith type is loaded in Mode I. We observe dislocation emission and twinning near the free sample surfaces and later plastically induced crack initiation.

Molecular dynamic studies of amyloid-beta interactions with curcumin and Cu2+ ions

2015 ◽  
Vol 69 (9) ◽  
Author(s):  
Stanislav Kozmon ◽  
Igor Tvaroška
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Molecular Dynamics ◽  
Transition Metals ◽  
Metal Ions ◽  
Molecular Dynamic ◽  
Amyloid Beta ◽  
Md Simulations ◽  
Aβ Peptide ◽  
Dynamic Studies

AbstractAmyloid-beta (Aβ) peptide readily forms aggregates that are associated with Alzheimer’s disease. Transition metals play a key role in this process. Recently, it has been shown that curcumin (CUA), a polyphenolic phytochemical, inhibits the aggregation of Aβ peptide. However, interactions of Aβ peptide with metal ions or CUA are not entirely clear. In this work, molecular dynamics (MD) simulations were carried out to clear the nature of interactions between the 42-residue Aβ peptide (Aβ-42) and Cu

Effects of Temperature on Crack Propagation of Nanocrystalline Nickel: A Molecular Dynamics Approach

2014 ◽  
Vol 926-930 ◽  
pp. 98-102
Author(s):  
Zi Qiang Li ◽  
Jin Gui Yu ◽  
Qiao Xin Zhang
Keyword(s):  
Molecular Dynamics ◽  
Crack Propagation ◽  
Great Influence ◽  
Crack Tip ◽  
Md Simulations ◽  
Mode I ◽  
Dislocation Emission ◽  
Nanocrystalline Nickel ◽  
Atomic Lattice ◽  
Effects Of Temperature

The primary purpose of this paper is to study the effects of temperature on crack propagation of nanocrystalline nickel by Molecular Dynamics (MD) simulations. Cracks are loaded in tension mode I. Results show that dislocation emission from a crack tip in nanocrystalline nickel due to the recombination of atomic lattice, then distortion of the crack tip promote crack propagation. The studies we have performed showed that temperature takes a great influence on the crack propagation and the crack shape, and we also found that the crack blunt obviously at high temperature.

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