Hierarchical Multiscale Modeling in Large and Plastic Deformations

Sarkari Khorrami, Mohammad | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 49006 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Khoei, Amir Reza
  7. Abstract:
  8. In this study, the hierarchical multiscale method is presented to model macro-scale materials with considering large and plastic deformations. Since the classic methods such as continuum mechanics were unable to model defects such as dislocations, voids, and etc. at nano scale. Also, the molecular dynamics methods have high computational costs; hence, recearchers try to develop multiscale methods in order to utilize them. Multiscale modeling in which two scales are considered and some information be transferred from fine scale to coarse scale. In this work, the coarse scale is modeled by finite element method (FEM) and the fine scale is analysed by molecular dynamics (MD). In fact, two scales, macro-nano, are considered in order to be modeled as multiscale method. Due to analyse ARVE (atomic representative volume element) using molecular dynamics, the plastic deformations can be created. Accordingly, the effect of dislocations or voids created by deformation gradient must be indicated in the constitutive material relations. In fact, the average stresses and tangent modulus are affected by these defects, which are in ARVEs. Therefore, this multiscale method can be used to anticipate mechanichal behavior for nano materials with large scale. Moreover, this method improves continuum mechanic model of macro domains whose mechanical properties are unknown
  9. Keywords:
  10. Molecular Dynamics ; Multiscale Modeling ; Dislocation ; Representative Volume Element ; Large Deformation ; Plastic Deformation

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