Strain Localization in a Molecular-Dynamics Model of a Metallic Glass

2002 ◽  
Vol 754 ◽  
Author(s):  
Michael L. Falk ◽  
Yunfeng Shi
Keyword(s):  
Molecular Dynamics ◽  
Strain Localization ◽  
Surface Defects ◽  
Amorphous Solid ◽  
Nanometer Scale ◽  
Length Scale ◽  
Two Dimensional ◽  
Free Boundaries ◽  
Dynamics Model ◽  
Dynamics Simulations

ABSTRACTMolecular dynamics simulations of a two-dimensional amorphous solid exhibit strain localization when loaded in uniaxial tension with free boundaries. The degree of localization depends sensitively on the rate of loading and on the existence of surface defects. Regions of both dilation and contraction arise during the shear band slip process. These dilation and contraction events correspond to dynamic free-volume generation and annihilation during shear. Correlations of the dilation and contraction of the material reveal a length scale of 1–4 atomic diameters associated with this physical process. Dilation is observed to result in nanometer scale cavitation.

Molecular Dynamics Simulations of Shock-Defect Interactions in Two-Dimensional Nonreactive Crystals

1992 ◽  
Vol 296 ◽  
Author(s):  
Robert S. Sinkovits ◽  
Lee Phillips ◽  
Elaine S. Oran ◽  
Jay P. Boris
Keyword(s):  
Molecular Dynamics ◽  
Hexagonal Lattice ◽  
Square Lattice ◽  
Two Dimensional ◽  
Connection Machine ◽  
Defect Sites ◽  
Principal Axes ◽  
Shock Motion ◽  
Defect Interactions ◽  
Dynamics Simulations

AbstractThe interactions of shocks with defects in two-dimensional square and hexagonal lattices of particles interacting through Lennard-Jones potentials are studied using molecular dynamics. In perfect lattices at zero temperature, shocks directed along one of the principal axes propagate through the crystal causing no permanent disruption. Vacancies, interstitials, and to a lesser degree, massive defects are all effective at converting directed shock motion into thermalized two-dimensional motion. Measures of lattice disruption quantitatively describe the effects of the different defects. The square lattice is unstable at nonzero temperatures, as shown by its tendency upon impact to reorganize into the lower-energy hexagonal state. This transition also occurs in the disordered region associated with the shock-defect interaction. The hexagonal lattice can be made arbitrarily stable even for shock-vacancy interactions through appropriate choice of potential parameters. In reactive crystals, these defect sites may be responsible for the onset of detonation. All calculations are performed using a program optimized for the massively parallel Connection Machine.

Substrate induced freezing, melting and depinning transitions in two-dimensional liquid crystalline systems

2022 ◽  
Author(s):  
Bharti bharti ◽  
Debabrata Deb
Keyword(s):  
Molecular Dynamics ◽  
Liquid Crystals ◽  
Molecular Dynamics Simulations ◽  
Liquid Crystalline ◽  
Two Dimensional ◽  
One Dimensional ◽  
The One ◽  
Dynamics Simulations

We use molecular dynamics simulations to investigate the ordering phenomena in two-dimensional (2D) liquid crystals over the one-dimensional periodic substrate (1DPS). We have used Gay-Berne (GB) potential to model the...

Effect of polymer–nanoparticle interaction on strain localization in polymer nanopillars

Soft Matter ◽  
2020 ◽  
Vol 16 (37) ◽  
pp. 8639-8646
Author(s):  
Entao Yang ◽  
Robert J. S. Ivancic ◽  
Emily Y. Lin ◽  
Robert A. Riggleman
Keyword(s):  
Molecular Dynamics ◽  
Shear Band ◽  
Molecular Dynamics Simulations ◽  
Strain Localization ◽  
Polymer Nanoparticle ◽  
Dynamics Simulations

We used molecular dynamics simulations to investigate the effect of NPs on the tendency of polymer nanopillar to form a shear band and found the polymer–NP interactions have a surprisingly strong effect on the location of a shear band in the sample.

Void and Dislocation Microstructure Development in Heteroepitaxial Film Growth

1995 ◽  
Vol 399 ◽  
Author(s):  
Richard W. Smith ◽  
David J. Srolovitz
Keyword(s):  
Thin Films ◽  
Molecular Dynamics ◽  
Film Growth ◽  
Lattice Misfit ◽  
Two Dimensional ◽  
Microstructure Development ◽  
Non Equilibrium Molecular Dynamics ◽  
Dynamics Simulations ◽  
Film Substrate ◽  
Edge Dislocations

ABSTRACTTwo dimensional, non-equilibrium molecular dynamics simulations have been performed to examine the microstructures of both homoepitaxial and heteroepitaxial thin films grown on single crystal substrates. The principal microstructural features to develop within these films are small voids and edge dislocations. Voids form near the surface of the growing film as surface depressions between microcolumns pinch off to become closed volumes. These voids often form in such a way as to introduce dislocations into the crystal with their cores positioned within the voids. Dislocations are also formed during heteroepitaxy at the interface between the substrate and film. These dislocations tend to be mobile. When voids are present in the film and when the lattice misfit is low, dislocations tend to be trapped in the voids or pulled toward them due to dislocation image interactions. Once attached to voids, dislocations are effectively pinned there. When voids are absent or when the misfit is high, dislocations are restricted to the film-substrate interface. In the case of heteroepitaxy, dislocations are found to relieve either tensile or compressive misfit stresses. Misfit stresses may also be accommodated, to some extent, merely by the free volume of the voids themselves.

Molecular dynamics simulations of energy dissipation and non-thermal diffusion on amorphous solid water

2018 ◽  
Vol 20 (8) ◽  
pp. 5569-5577 ◽  
Author(s):  
A. Fredon ◽  
H. M. Cuppen
Keyword(s):  
Molecular Dynamics ◽  
Energy Dissipation ◽  
Molecular Dynamics Simulations ◽  
Gas Phase ◽  
Thermal Diffusion ◽  
Amorphous Solid ◽  
Gas Phase Reactions ◽  
Amorphous Solid Water ◽  
Dynamics Simulations ◽  
Dust Grain

Molecules in space are synthesized via a large variety of gas-phase reactions, and reactions on dust-grain surfaces, where the surface acts as a catalyst.

Molecular dynamics simulations on the dynamics of two-dimensional rounded squares

2018 ◽  
Vol 27 (8) ◽  
pp. 088203 ◽  
Author(s):  
Zhang-lin Hou ◽  
Ying Ju ◽  
Yi-wu Zong ◽  
Fang-fu Ye ◽  
Kun Zhao
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Two Dimensional ◽  
Dynamics Simulations
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