scholarly journals Mechanical Properties of Protomene: A Molecular Dynamics Investigation

MRS Advances ◽  
2019 ◽  
Vol 4 (3-4) ◽  
pp. 191-196 ◽  
Author(s):  
Eliezer F. Oliveira ◽  
Pedro A. S. Autreto ◽  
Cristiano F. Woellner ◽  
Douglas S. Galvao
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Ultimate Strength ◽  
Carbon Allotrope ◽  
Mechanical Fracture ◽  
Reactive Molecular Dynamics ◽  
New Class ◽  
A Value ◽  
Reaxff Force Field ◽  
Dynamics Simulations

ABSTRACTRecently, a new class of carbon allotrope called protomene was proposed. This new structure is composed of sp2 and sp3 carbon-bonds. Topologically, protomene can be considered as an sp3 carbon structure (∼80% of this bond type) doped by sp2 carbons. First-principles simulations have shown that protomene presents an electronic bandgap of ∼3.4 eV. However, up to now, its mechanical properties have not been investigated. In this work, we have investigated protomene mechanical behavior under tensile strain through fully atomistic reactive molecular dynamics simulations using the ReaxFF force field, as available in the LAMMPS code. At room temperature, our results show that the protomene is very stable and the obtained ultimate strength and ultimate stress indicates an anisotropic behavior. The highest ultimate strength was obtained for the x-direction, with a value of ∼110 GPa. As for the ultimate strain, the highest one was for the z-direction (∼25% of strain) before protomene mechanical fracture.

scholarly journals Mechanical Properties of Phagraphene Membranes: A Fully Atomistic Molecular Dynamics Investigation

MRS Advances ◽  
2018 ◽  
Vol 3 (1-2) ◽  
pp. 67-72 ◽  
Author(s):  
J. M. de Sousa ◽  
A. L. Aguiar ◽  
E. C. Girão ◽  
Alexandre F. Fonseca ◽  
A. G. Sousa Filho ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Carbon Allotrope ◽  
Reactive Molecular Dynamics ◽  
Elastic Regime ◽  
Fracture Patterns ◽  
Anisotropic Thermal Conductivity ◽  
Reaxff Force Field ◽  
Dynamics Simulations ◽  
Comprehensive Study

ABSTRACTRecently, a new 2D carbon allotrope structure, named phagraphene (PG), was proposed. PG has a densely array of penta-hexa-hepta-graphene carbon rings. PG was shown to present low and anisotropic thermal conductivity and it is believed that this anisotropy should be also reflected in its mechanical properties. Although PG mechanical properties have been investigated, a detailed and comprehensive study is still lacking. In the present work we have carried out fully atomistic reactive molecular dynamics simulations using the ReaxFF force field, to investigate the mechanical properties and fracture patterns of PG membranes. The Young’s modulus values of the PG membranes were estimated from the stress-strain curves. Our results show that these curves present three distinct regimes: one regime where ripples dominate the structure and mechanical properties of the PG membranes; an elastic regime where the membranes exhibit fully planar configurations; and finally am inelastic regime where permanent deformations happened to the PG membrane up to the mechanical failure or fracture.

scholarly journals Mechanical Properties of Schwarzites - A Fully Atomistic Reactive Molecular Dynamics Investigation

MRS Advances ◽  
2018 ◽  
Vol 3 (8-9) ◽  
pp. 451-456 ◽  
Author(s):  
Cristiano F. Woellner ◽  
Tiago Botari ◽  
Eric Perim ◽  
Douglas S. Galvão
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Compressive Strain ◽  
Porous Structures ◽  
Mechanical Compression ◽  
Structural Failure ◽  
Reactive Molecular Dynamics ◽  
Reaxff Force Field ◽  
Original Size ◽  
Dynamics Simulations

ABSTRACTSchwarzites are crystalline, 3D porous structures with a stable negative curvature formed of sp2-hybridized carbon atoms. These structures present topologies with tunable porous size and shape and unusual mechanical properties. In this work, we have investigated the mechanical behavior under compressive strain and energy absorption of four different Schwarzites. We considered two Schwarzites families, the so-called Gyroid and Primitive and two structures from each family. We carried out reactive molecular dynamics simulations, using the ReaxFF force field as available in the LAMMPS code. Our results also show they exhibit remarkable resilience under mechanical compression. They can be reduced to half of their original size before structural failure (fracture) occurs.

scholarly journals Mechanical Properties of Pentagraphene-based Nanotubes: A Molecular Dynamics Study

MRS Advances ◽  
2018 ◽  
Vol 3 (1-2) ◽  
pp. 97-102 ◽  
Author(s):  
J. M. de Sousa ◽  
A. L. Aguiar ◽  
E. C. Girão ◽  
Alexandre F. Fonseca ◽  
A. G. Souza Filho ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Molecular Dynamics ◽  
Elastic Behavior ◽  
Fracture Patterns ◽  
Nanostructured Systems ◽  
Reaxff Force Field ◽  
Dynamics Simulations ◽  
Different Diameters ◽  
Graphene Membranes

ABSTRACTThe study of the mechanical properties of nanostructured systems has gained importance in theoretical and experimental research in recent years. Carbon nanotubes (CNTs) are one of the strongest nanomaterials found in nature, with Young’s Modulus (EY) in the order 1.25 TPa. One interesting question is about the possibility of generating new nanostructures with 1D symmetry and with similar and/or superior CNT properties. In this work, we present a study on the dynamical, structural, mechanical properties, fracture patterns and EY values for one class of these structures, the so-called pentagraphene nanotubes (PGNTs). These tubes are formed rolling up pentagraphene membranes (which are quasi-bidimensional structures formed by densely compacted pentagons of carbon atoms in sp3 and sp2 hybridized states) in the same form that CNTs are formed from rolling up graphene membranes. We carried out fully atomistic molecular dynamics simulations using the ReaxFF force field. We have considered zigzag-like and armchair-like PGNTs of different diameters. Our results show that PGNTs present EY ∼ 800 GPa with distinct elastic behavior in relation to CNTs, mainly associated with mechanical failure, chirality dependent fracture patterns and extensive structural reconstructions.

Schwarzites to schwarzynes: A new class of superdeformable materials

MRS Advances ◽  
2020 ◽  
Vol 5 (37-38) ◽  
pp. 1947-1954
Author(s):  
Eliezer Fernando Oliveira ◽  
Douglas Soares Galvao
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Force Field ◽  
Molecular Dynamics Simulations ◽  
Elastic Properties ◽  
High Temperatures ◽  
Preliminary Results ◽  
New Class ◽  
Elastic Regime ◽  
Dynamics Simulations

AbstractIn this work, we have investigated the structural and mechanical properties of a new class of soft and superelastic materials, called schwarzynes. These materials are obtained by inserting sp carbon atoms (acetylenic groups) into the schwarzite framework. Using fully atomistic molecular dynamics simulations with the AIREBO force field, our results show that schwarzynes are stable materials up to high temperatures (1000K). Schwarzynes exhibit a very wide elastic regime, some of them up to 70% strain without structural fractures. Our preliminary results show that the elastic properties can be easily engineered by tuning the number of acetylenic groups and the crystallographic directions where they are inserted.

scholarly journals Site Dependent Hydrogenation in Graphynes: A Fully Atomistic Molecular Dynamics Investigation

2015 ◽  
Vol 1726 ◽  
Author(s):  
Pedro A. S. Autreto ◽  
Douglas S. Galvao
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Bonding ◽  
Structural Changes ◽  
Hydrogen Atoms ◽  
Carbon Allotrope ◽  
Reactive Molecular Dynamics ◽  
Triple Bonds ◽  
Covalently Bonded ◽  
Hydrogenation Reactions ◽  
Dynamics Simulations

ABSTRACTGraphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of α, β, and γ graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the α, β, γ-graphyne structure ordering.

scholarly journals Effect of Angle, Temperature and Vacancy Defects on Mechanical Properties of PSI-Graphene

Crystals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 238 ◽  
Author(s):  
Lu Xie ◽  
Tingwei Sun ◽  
Chenwei He ◽  
Haojie An ◽  
Qin Qin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Ultimate Strength ◽  
Fracture Morphology ◽  
Dynamics Simulation ◽  
Dimensional Structure ◽  
Two Dimensional ◽  
Carbon Allotrope ◽  
Vacancy Defects ◽  
Carbon Structures

The PSI-graphene, a two-dimensional structure, was a novel carbon allotrope. In this paper, based on molecular dynamics simulation, the effects of stretching direction, temperature and vacancy defects on the mechanical properties of PSI-graphene were studied. We found that when PSI-graphene was stretched along 0° and 90° at 300 K, the ultimate strength reached a maximum of about 65 GPa. And when stretched along 54.2° and 155.2° at 300 K, the Young’s modulus had peaks, which were 1105 GPa and 2082 GPa, respectively. In addition, when the temperature was raised from 300 K to 900 K, the ultimate strength in all directions was reduced. The fracture morphology of PSI-graphene stretched at different angles was also shown in the text. In addition, the number of points removed from PSI-graphene sheet also seriously affected the tensile properties of the material. It was found that, compared with graphene, PSI-graphene didn’t have the negative Poisson’s ratio phenomenon when it was stretched along the direction of 0°, 11.2°, 24.8° and 34.7°. Our results provided a reference for studying the multi-angle stretching of other carbon structures at various temperatures.

scholarly journals Reactive Molecular Dynamics Simulations On Thermal Decomposition of 3-Methyl-2,6-Dinitrophenol

2021 ◽  
Author(s):  
Jiaxiang Zhao ◽  
Yun Xiao ◽  
Jiayuan He ◽  
Jianlong Wang
Keyword(s):  
Molecular Dynamics ◽  
Thermal Decomposition ◽  
Intermediate Product ◽  
Md Simulations ◽  
Heating Rates ◽  
Intermediate Products ◽  
Reactive Molecular Dynamics ◽  
Reaxff Force Field ◽  
Dynamics Simulations ◽  
Time Required

Abstract The decomposition mechanism of 3-methyl-2,6-dinitrophenol (MDNP) was simulated by reaction molecular dynamics using ReaxFF force field. The evolution of some main products with time at different heating rates (10, 15 and 20 K·ps-1) were obtained as well. The simulation outcomes reveal that with the elevation of the heating rate, the shorter the time required for the system to reach equilibrium, and the more products are produced. At three heating rates, the main intermediate products are C7H7O5N2, C7H6O4N2, C7H5O5N2, C7H5O4N2, HON, NO, NO2 and the primary final products are N2, CO2, H2O, H2, NH3, amongst which C7H5O5N2 is the first produced intermediate product and H2O is the first produced final product with the biggest abundance. The intermediate products first increase and then decrease to zero. Moreover, the primary chemistry reactions in the MDNP pyrolysis are acquired by ReaxFF MD simulations.

Graphyne Oxidation: Insights From a Reactive Molecular Dynamics Investigation

2013 ◽  
Vol 1549 ◽  
pp. 53-58 ◽  
Author(s):  
L. D. Machado ◽  
P. A. S. Autreto ◽  
D. S. Galvao
Keyword(s):  
Molecular Dynamics ◽  
Structural Changes ◽  
Single Layer ◽  
Oxidation Reactions ◽  
Carbon Allotrope ◽  
Reactive Molecular Dynamics ◽  
Triple Bonds ◽  
Covalently Bonded ◽  
Dynamics Simulations ◽  
Oxygen Atoms

ABSTRACTGraphyne is a generic name for a family of carbon allotrope two-dimensional structures where sp2 (single and double bonds) and sp (triple bonds) hybridized states coexists. They exhibit very interesting electronic and mechanical properties sharing some of the unique graphene characteristics. Similarly to graphene, the graphyne electronic properties can be modified by chemical functionalization, such as; hydrogenation, fluorination and oxidation. Oxidation is of particular interest since it can produce significant structural damages.In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the oxidation of single-layer graphyne membranes at room temperature. We have considered α, β, and γ-graphyne structures. Our results showed that the oxidation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. Our results also showed that the effectiveness of the oxidation (estimated from the number of oxygen atoms covalently bonded to carbon atoms) follows the α, β, γ-graphyne structure ordering. These differences can be explained by the fact that for α-graphyne structures the oxidation reactions occur in two steps: first, the oxygen atoms are trapped at the center of the large polygonal rings and then they react with the carbon atoms composing of the triple bonds. The small rings of γ-graphyne structures prevent these reactions to occur. The effectiveness of β-graphyne oxidation is between the α- and γ-graphynes.

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