Multiscale Modeling of Carbon Nano Structures Using Tersoff Potential Function

Najjari, Alireza | 2014

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  1. Type of Document: M.Sc. Thesis
  2. Language: English
  3. Document No: 46855 (53)
  4. University: Sharif University of Technology, International Campus, Kish Island
  5. Department: Science and Engineering
  6. Advisor(s): Khoei, Amir Reza
  7. Abstract:
  8. During the last decade, thanks to a combination of exploding computational power and improved physical insight into material behavior, continuum and atomistic simulations improved greatly. Both classes of methods are now used to solve problems, which are more complicated than ever with greater accuracy than ever before. Nevertheless, there still exist problems for which neither method alone is sufficient. In general, atomistic simulations cannot be used for such length scales due to the restrictions on the number of atoms that can be simulated, along with the time scales, which they can be simulated for. In contrast, continuum simulations tend to fail at the atomic scale, for example due to the inability of continuum models to describe defects. It is precisely at these length scales, where multi-scale simulation methods are needed [1]. In the provided research, a concurrent multi-scale method is used to solve the molecular dynamics and finite element method simultaneously. Also the stiffness matrix is provided using derivation from Tersoff potential function in order to study the mechanical behavior of carbon nano structures. In this method, the finite element stiffness matrix, which is obtained by the underlying atoms, is transferred to the finite element meshes through a linear transformation matrix. The two-way nature of the coupled FE and reduced MD equations of motion is demonstrated via some examples in carbon nano structures. Finally, each problem is compared to benchmark full MD simulations to validate the accuracy and efficiency of the proposed method
  9. Keywords:
  10. Multiscale Modeling ; Graphine ; Carbon Nanotubes ; Molecular Modeling ; Tersoff Potential Function

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