scholarly journals Finite-temperature elasticity of fcc Al: Atomistic simulations and ultrasonic measurements

2011 ◽  
Vol 84 (6) ◽  
Author(s):  
Hieu H. Pham ◽  
Michael E. Williams ◽  
Patrick Mahaffey ◽  
Miladin Radovic ◽  
Raymundo Arroyave ◽  
...  
Keyword(s):  
Finite Temperature ◽  
Atomistic Simulations ◽  
Ultrasonic Measurements

scholarly journals Atomistic Simulations of Dislocations in Confined Volumes

MRS Bulletin ◽  
2009 ◽  
Vol 34 (3) ◽  
pp. 184-189 ◽  
Author(s):  
P.M. Derlet ◽  
P. Gumbsch ◽  
R. Hoagland ◽  
J. Li ◽  
D.L. McDowell ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Time Scale ◽  
Finite Temperature ◽  
Atomistic Simulation ◽  
Dislocation Nucleation ◽  
Atomic Scale ◽  
Atomistic Simulations ◽  
Complementary Role ◽  
Nanocrystalline Structures ◽  
Strength And Ductility

AbstractInternal microstructural length scales play a fundamental role in the strength and ductility of a material. Grain boundaries in nanocrystalline structures and heterointerfaces in nanolaminates can restrict dislocation propagation and also act as a source for new dislocations, thereby affecting the detailed dynamics of dislocation-mediated plasticity. Atomistic simulation has played an important and complementary role to experiment in elucidating the nature of the dislocation/interface interaction, demonstrating a diversity of atomic-scale processes covering dislocation nucleation, propagation, absorption, and transmission at interfaces. This article reviews some atomistic simulation work that has made progress in this field and discusses possible strategies in overcoming the inherent time scale challenge of finite temperature molecular dynamics.

scholarly journals Finite-temperature properties of the relaxorPbMg1/3Nb2/3O3from atomistic simulations

2015 ◽  
Vol 91 (21) ◽  
Author(s):  
A. Al-Barakaty ◽  
Sergey Prosandeev ◽  
Dawei Wang ◽  
B. Dkhil ◽  
L. Bellaiche
Keyword(s):  
Finite Temperature ◽  
Atomistic Simulations

scholarly journals A Hybrid Molecular Dynamics/Atomic-Scale Finite Element Method for Quasi-Static Atomistic Simulations at Finite Temperature

2013 ◽  
Vol 81 (5) ◽  
Author(s):  
Ran Xu ◽  
Bin Liu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Temperature ◽  
Simulation Method ◽  
Atomic Scale ◽  
Atomistic Simulations ◽  
Single Wall Carbon Nanotubes ◽  
Equilibrium Configurations ◽  
Quasi Static Process ◽  
Element Method

In this paper, a hybrid quasi-static atomistic simulation method at finite temperature is developed, which combines the advantages of MD for thermal equilibrium and atomic-scale finite element method (AFEM) for efficient equilibration. Some temperature effects are embedded in static AFEM simulation by applying the virtual and equivalent thermal disturbance forces extracted from MD. Alternatively performing MD and AFEM can quickly obtain a series of thermodynamic equilibrium configurations such that a quasi-static process is modeled. Moreover, a stirring-accelerated MD/AFEM fast relaxation approach is proposed in which the atomic forces and velocities are randomly exchanged to artificially accelerate the “slow processes” such as mechanical wave propagation and thermal diffusion. The efficiency of the proposed methods is demonstrated by numerical examples on single wall carbon nanotubes.

Coupled Atomistic/Discrete Dislocation Simulations of Nanoindentation at Finite Temperature

2005 ◽  
Vol 127 (4) ◽  
pp. 358-368 ◽  
Author(s):  
Behrouz Shiari ◽  
Ronald E. Miller ◽  
William A. Curtin
Keyword(s):  
Finite Temperature ◽  
Computational Cost ◽  
Computational Method ◽  
Atomistic Simulations ◽  
Computational Framework ◽  
Reflected Waves ◽  
Indentation Process ◽  
Discrete Dislocation ◽  
Atomistic Region ◽  
System Temperature

Simulations of nanoindentation in single crystals are performed using a finite temperature coupled atomistic/continuum discrete dislocation (CADD) method. This computational method for multiscale modeling of plasticity has the ability of treating dislocations as either atomistic or continuum entities within a single computational framework. The finite-temperature approach here inserts a Nose-Hoover thermostat to control the instantaneous fluctuations of temperature inside the atomistic region during the indentation process. The method of thermostatting the atomistic region has a significant role on mitigating the reflected waves from the atomistic/continuum boundary and preventing the region beneath the indenter from overheating. The method captures, at the same time, the atomistic mechanisms and the long-range dislocation effects without the computational cost of full atomistic simulations. The effects of several process variables are investigated, including system temperature and rate of indentation. Results and the deformation mechanisms that occur during a series of indentation simulations are discussed.

Finite-temperature properties of(Ba,Sr)TiO3systems from atomistic simulations

2006 ◽  
Vol 73 (14) ◽  
Author(s):  
Laura Walizer ◽  
Sergey Lisenkov ◽  
L. Bellaiche
Keyword(s):  
Finite Temperature ◽  
Atomistic Simulations
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