Fracture Toughness and Surface Energy Density of Kerogen by Molecular Dynamics Simulations in Tensile Failure

2020 ◽  
Vol 124 (29) ◽  
pp. 15895-15901 ◽  
Author(s):  
Tianhao Wu ◽  
Abbas Firoozabadi
Keyword(s):  
Molecular Dynamics ◽  
Fracture Toughness ◽  
Energy Density ◽  
Surface Energy ◽  
Molecular Dynamics Simulations ◽  
Tensile Failure ◽  
Surface Energy Density ◽  
Dynamics Simulations

Length-dependent dual-mechanism-controlled failure modes in silver penta-twinned nanowires

Nanoscale ◽  
2018 ◽  
Vol 10 (44) ◽  
pp. 20565-20577 ◽  
Author(s):  
Tianshou Liang ◽  
Dejian Zhou ◽  
Zhaohua Wu ◽  
Pengpeng Shi ◽  
Xiaoyong Chen
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Failure Modes ◽  
Failure Mechanisms ◽  
Tensile Failure ◽  
Fracture Surfaces ◽  
Dynamics Simulations ◽  
Dual Mechanism

A series of molecular dynamics simulations on silver penta-twinned nanowires are performed to reveal the tensile failure mechanisms that are responsible for the different failure modes and morphologies of fracture surfaces observed in various experimental reports.

scholarly journals Surface energy of nanoparticles – influence of particle size and structure

2018 ◽  
Vol 9 ◽  
pp. 2265-2276 ◽  
Author(s):  
Dieter Vollath ◽  
Franz Dieter Fischer ◽  
David Holec
Keyword(s):  
Molecular Dynamics ◽  
Particle Size ◽  
Surface Energy ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Molecular Dynamics Simulations ◽  
Definition Of ◽  
Dynamics Simulations ◽  
Classical Thermodynamics ◽  
A Minor

The surface energy, particularly for nanoparticles, is one of the most important quantities in understanding the thermodynamics of particles. Therefore, it is astonishing that there is still great uncertainty about its value. The uncertainty increases if one questions its dependence on particle size. Different approaches, such as classical thermodynamics calculations, molecular dynamics simulations, and ab initio calculations, exist to predict this quantity. Generally, considerations based on classical thermodynamics lead to the prediction of decreasing values of the surface energy with decreasing particle size. This phenomenon is caused by the reduced number of next neighbors of surface atoms with decreasing particle size, a phenomenon that is partly compensated by the reduction of the binding energy between the atoms with decreasing particle size. Furthermore, this compensating effect may be expected by the formation of a disordered or quasi-liquid layer at the surface. The atomistic approach, based either on molecular dynamics simulations or ab initio calculations, generally leads to values with an opposite tendency. However, it is shown that this result is based on an insufficient definition of the particle size. A more realistic definition of the particle size is possible only by a detailed analysis of the electronic structure obtained from initio calculations. Except for minor variations caused by changes in the structure, only a minor dependence of the surface energy on the particle size is found. The main conclusion of this work is that surface energy values for the equivalent bulk materials should be used if detailed data for nanoparticles are not available.

Tunable Gigahertz Oscillators of Gliding Incommensurate Bilayer Graphene Sheets

2013 ◽  
Vol 80 (4) ◽  
Author(s):  
Ming Luo ◽  
Zhuhua Zhang ◽  
Boris I. Yakobson
Keyword(s):  
Molecular Dynamics ◽  
Surface Energy ◽  
Molecular Dynamics Simulations ◽  
Friction Force ◽  
Function Theory ◽  
Bilayer Graphene ◽  
Atomistic Simulations ◽  
Graphene Sheets ◽  
Dynamics Simulations ◽  
Oscillation Frequencies

Oscillators composed of incommensurate graphene sheets have been investigated by molecular dynamics simulations. The oscillation frequencies can reach tens of gigahertz range and depend on the surface energy of the bilayer graphene and the oscillatory amplitude. We demonstrate the tunability of such an oscillator in terms of frequency and friction by its varying geometric parameters. Exploration of the damping mechanism by combining the autocorrelation function theory and the direct atomistic simulations reveals that the friction force is proportional to the velocity of oscillatory motion. The results should help optimize the design of graphene-based nanoelectromechanical devices.

Simulation by classical molecular dynamics of the influence of radiation effects on the fracture behavior of simplified nuclear glasses

2012 ◽  
Vol 1475 ◽  
Author(s):  
Le-Hai Kieu ◽  
Jean-Marc Delaye ◽  
Claude Stolz
Keyword(s):  
Molecular Dynamics ◽  
Fracture Toughness ◽  
Molecular Dynamics Simulations ◽  
Radiation Effects ◽  
Fracture Behavior ◽  
Elastic Limit ◽  
Experimental Results ◽  
Displacement Cascades ◽  
Classical Molecular Dynamics ◽  
Dynamics Simulations

ABSTRACTClassical molecular dynamics simulations were used to compare the fracture behavior of pristine and disordered specimens of a simplified nuclear glass. The disordered specimen is prepared in order to mimic the effects of accumulating displacement cascades. It is characterized by a decreasing Boron coordination and an increasing Na concentration in a modifying role. We observe an enhancement of the plasticity of the disordered glass and a decrease of the elastic limit, resulting in greater fracture toughness. The simulation findings are consistent with experimental results.

scholarly journals Fracture toughness of sodium aluminosilicate hydrate (NASH) gels: Insights from molecular dynamics simulations

2020 ◽  
Vol 127 (16) ◽  
pp. 165107 ◽  
Author(s):  
Gideon A. Lyngdoh ◽  
Sumeru Nayak ◽  
Rajesh Kumar ◽  
N. M. Anoop Krishnan ◽  
Sumanta Das
Keyword(s):  
Molecular Dynamics ◽  
Fracture Toughness ◽  
Molecular Dynamics Simulations ◽  
Sodium Aluminosilicate ◽  
Dynamics Simulations ◽  
Sodium Aluminosilicate Hydrate
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