Coarse-Grained Molecular Dynamics for Computer Modeling of Nanomechanical Systems

Rudd, Robert E.

doi:10.1615/intjmultcompeng.v2.i2.30

Cited by 26 publications

(21 citation statements)

References 60 publications

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“…We have developed techniques that are able to embed molecular dynamics in a continuum simulation, either using finite elements [23] or a more seamless technique known as coarse-grained molecular dynamics (CGMD) [24][25][26]. These techniques work best for inhomogeneous systems, in which there is only a relatively small region of the system in which atomistic resolution is needed.…”

Section: On-the-fly Multiscale Modeling Of Damagementioning

confidence: 99%

Void coalescence processes quantified through atomistic and multiscale simulation

Rudd

Seppälä

Dupuy

et al. 2007

J Computer-Aided Mater Des

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Simulation of ductile fracture at the atomic scale reveals many aspects of the fracture process including specific mechanisms associated with void nucleation and growth as a precursor to fracture and the plastic deformation of the material surrounding the voids and cracks. Recently we have studied void coalescence in ductile metals using large-scale atomistic and continuum simulations. Here we review that work and present some related investigations. The atomistic simulations involve threedimensional strain-controlled multi-million atom molecular dynamics simulations of copper. The correlated growth of two voids during the coalescence process leading to fracture is investigated, both in terms of its onset and the ensuing dynamical interactions. Void interactions are quantified through the rate of reduction of the distance between the voids, through the correlated directional growth of the voids, and through correlated shape evolution of the voids. The critical inter-void ligament distance marking the onset of coalescence is shown to be approximately one void radius based on the quantification measurements used, independent of the initial separation distance between the voids and the strain-rate of the expansion of the system. No pronounced shear flow is found in the coalescence process.

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Section: On-the-fly Multiscale Modeling Of Damagementioning

confidence: 99%

Void coalescence processes quantified through atomistic and multiscale simulation

Rudd

Seppälä

Dupuy

et al. 2007

J Computer-Aided Mater Des

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“…Finite element modeling is an approach to discretization of partial differential equations by introduction of an irregular mesh. The FEM expression for the potential energy is [11]:…”

Section: P Yang and N Liaomentioning

confidence: 99%

“…This integral may be computed analytically in some cases, or through numerical quadrature more generally. The stiffness matrix is assembled element by element for efficiency, so that even though there is a global stiffness matrix given by K iaj b = I K iaj b;I [11].…”

Section: P Yang and N Liaomentioning

confidence: 99%

A novel MD/FE coupled model for numerical investigation of interfacial thermal resistance in MEMS/NEMS packaging

Yang

Liao

2008

Composite Interfaces

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“…Another example is a Nano-Electro-Mechanical System (NEMS) resonator. 9,10,11,12 It consists of a semiconductor bar about 50 nm wide and a fraction of a micron long attached to the substrate at both ends. The bar itself is clearly nanoscale, and yet as it resonates, the oscillating strain fields extend far into the substrate.…”

Section: 2mentioning

confidence: 99%

Coarse-grained molecular dynamics: Nonlinear finite elements and finite temperature

2005

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Coarse-grained molecular dynamics (CGMD) is a technique developed as a concurrent multiscale model that couples conventional molecular dynamics (MD) to a more coarse-grained description of the periphery. The coarse-grained regions are modeled on a mesh in a formulation that generalizes conventional finite element modeling (FEM) of continuum elasticity. CGMD is derived solely from the MD model, however, and has no continuum parameters. As a result, it provides a coupling that is smooth and provides control of errors that arise at the coupling between the atomistic and coarse-grained regions. In this article, we elaborate on the formulation of CGMD, describing in detail how CGMD is applied to anharmonic solids and finite temperature simulations. As tests of CGMD, we present in detail the calculation of the phonon spectra for solid argon and tantalum in 3D, demonstrating how CGMD provides a better description of the elastic waves than that provided by FEM. We also present elastic wave scattering calculations that show the elastic wave scattering is more benign in CGMD than FEM. We also discuss the dependence of scattering on the properties of the mesh. We introduce a rigid approximation to CGMD that eliminates internal relaxation, similar to the Quasicontinuum technique, and compare it to the full CGMD.

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Coarse-Grained Molecular Dynamics for Computer Modeling of Nanomechanical Systems

Cited by 26 publications

References 60 publications

Void coalescence processes quantified through atomistic and multiscale simulation

Void coalescence processes quantified through atomistic and multiscale simulation

A novel MD/FE coupled model for numerical investigation of interfacial thermal resistance in MEMS/NEMS packaging

Coarse-grained molecular dynamics: Nonlinear finite elements and finite temperature

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