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Hyperelastic Modeling of Atomistic Continuum in the Presence of Inhomogeneity

Asadollahzadeh, Niloofar | 2018

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  1. Type of Document: M.Sc. Thesis
  2. Language: English
  3. Document No: 51392 (53)
  4. University: Sharif University of Technology, International Campus, Kish Island
  5. Department: Science and Engineering
  6. Advisor(s): Khoei, Amir Reza; Jahanshahi, Mohsen
  7. Abstract:
  8. In this study, a pioneer multiscale hierarchical molecular dynamics (MD) – finite element (FE) coupling method is proposed to illustrate the influence of large deformation on mechanical properties of heterogeneous nano-crystalline structures. The embedded-atom method (EAM) of many-body interatomic potential is applied to evaluate pairwise interactions between atoms in the metallic alloys with face-centered-cubic (FCC) lattice structure at room temperature. In addition, the Nose-Hoover thermostat is used to control the instability of temperature. A weight average between the lattice parameters of atomic structures is utilized in order to calculate the equivalent lattice parameter. The surfaces and curves of strain energy density are obtained with respect to quantities of strain energy density corresponding to representative volume elements (RVE’s) subjected to biaxial and shear deformation loadings based on atomistic simulation. The elastic constants C11, C12, and C44 are found from the slope of the elastic regime of the stress-strain curves, where the growth of stress versus strain is linear. Then, the changes of yield stress points, elastic constants, and bulk modulus (B) are reported for crystal Cu RVE at various concentration levels of Al impurities. For a connection between atomistic (nano-scale) level and continuum (macro-scale) level, the mechanical properties are attained at the atomistic level and hyperelasticity theory transfer them to the continuum level
  9. Keywords:
  10. Multiscale Hierarchical Analysis ; Molecular Dynamics ; Nonlinear Finite Element Method ; Nonlinear Continuum Mechanics ; Large Deformation ; Hyperelasticity

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