1 / 4

Hierarchical Atomistic Simulation Methods

Hierarchical Atomistic Simulation Methods. Molecular Dynamics (MD). Electron wave function. Atom. ReaxFF. Train. Adaptive E MD. First principles-based reactive force-field (in collaboration with Goddard at Caltech). Quantum Mechanics (QM).

kirk
Télécharger la présentation

Hierarchical Atomistic Simulation Methods

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Hierarchical Atomistic Simulation Methods Molecular Dynamics (MD) Electron wave function Atom ReaxFF Train Adaptive EMD First principles-based reactive force-field (in collaboration with Goddard at Caltech) Quantum Mechanics (QM) Embedded divide-&-conquer (EDC) algorithm on adaptive multigrids for linear-scaling density functional theory (DFT) P. Vashishta, R. Kalia, A. Nakano DMR-0427188 W. Goddard, T. Cagin, P. Meulbroek, M. Ortiz, A. van Duin DMR-0427177 and A. Grama DMR-0427540

  2. Scalable Parallel Molecular Dynamics Algorithms Design-space diagram on 1,920 Itanium2 (1.5GHz) procs. of NASA Columbia • 19 billion-atom multiresolution molecular dynamics (MRMD) of SiO2 • 0.56 billion-atom fast reactive force-field (F-ReaxFF) MD of RDX • 1.4 million-atom (0.12 trillion grid points) embedded divide-&-conquer density functional theory (EDC-DFT) MD of Al2O3

  3. Nanoindentation on Nanophase SiC 19 million-atom MD simulation Load-displacement curve Hardness MD: 39 GPa (grain size, d = 8 nm) Expt.: 30-50 GPa (d = 5-20 nm) [Liao et al., APL, ‘05] “A crossover in the mechanical response of nanocrystalline ceramics” Science309, 911 (2005)

  4. Crossover in Mechanical Responses Crossover from intergrain continuous response to intragranular discrete response White: ordered atoms (12 6-membered rings) Yellow: disordered atoms Blue: disorder-to-order change Red: order-to-disorder change Mixture of crystalline grains & amrphous grain boundary phases “A crossover in the mechanical response of nanocrystalline ceramics” Science309, 911 (2005)

More Related