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Vibrational analysis of Ag, Cu and Ni nanobeams using a hybrid continuum-atomistic model
, Article International Journal of Mechanical Sciences ; Volume 165 , 2020 ; Azizi, B ; Nejat Pishkenari, H ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
An important issue in the study of the nanostructures behaviors is the surface effects, which increases with the increase of the surface-to-volume ratio. Continuum theories are capable of modeling structures at micro and larger scales with enough precision and low computational costs. However, these theories are unable to predict the mechanical properties of nanostructures accurately. On the other hand, due to their high precision, atomistic modeling techniques are extensively employed for the study of systems at nanoscale; however, computational costs of these techniques are relatively high. In this research, we aim to study the vibrational behavior of nanobeams made of three FCC metals;...
Molecular Dynamic Simulation of the Straining of Nano Cluster Aggregate
,
M.Sc. Thesis
Sharif University of Technology
;
Khoei, Amir Reza
(Supervisor)
Abstract
We carry out computer simulations in the hope of understanding the properties of assemblies of molecules in terms of their structure and the microscopic interactions between them. This serves as a complement to conventional experiments, enabling us to learn something new, something that cannot be found out in other ways. One of the main families of simulation technique are molecular dynamics (MD). Over the last decade , nanoscience and nanotechnology have emerged as two of the pillars of the research that will lead us to the next industrial revolution. The fundamental entities of interest to nanoscience and nanotechnology are the isolated individual nanostructures and their assemblies. Nano...
Coarse-graining models for molecular dynamics simulations of FCC metals
, Article Journal of Theoretical and Applied Mechanics (Poland) ; Volume 56, Issue 3 , 2018 , Pages 601-614 ; 14292955 (ISSN) ; Nejat Pishkenari, H ; Sharif University of Technology
Polish Society of Theoretical and Allied Mechanics
2018
Abstract
In this paper, four coarse-graining (CG) models are proposed to accelerate molecular dynamics simulations of FCC metals. To this aim, at first, a proper map between beads of the CG models and atoms of the all-atom (AA) system is assigned, afterwards mass of the beads and the parameters of the CG models are determined in a manner that the CG models and the original all-atom model have the same physical properties. To evaluate and compare precision of these four CG models, different static and dynamic simulations are conducted. The results show that these CG models are at least 4 times faster than the AA model, while their errors are less than 1 percent. © 2018 Polish Society of Theoretical...
Determining Mechanical Properties of Particulate Metal Matrix Nanocomposites by Numerical Method
, M.Sc. Thesis Sharif University of Technology ; Naghdabadi, Reza (Supervisor) ; Sohrabpour, Saeed (Supervisor)
Abstract
Using materials with better mechanical properties is always advantageous. Many sectors, including automotive and aerospace industries, are always seeking new materials with better mechanical properties and lower weight. A lighter vehicle means lower emission and higher fuel efficiency. Thus, developing new methods to investigate novel materials is very important. One of these novel materials are Metal Matrix NanoComposites (MMNCs). MMNCs are fabricated using nano scale particles embedded in metallic matrix. High strength, stiffness, and hardness are the three most important mechanical properties of MMNCs. Introducing a suitable way of modeling these materials is important since it will...
Mechanical Behavior of Metalic Nano-structures Using a Nonlinear Multi-scale Model Based on Coarse Graining Approach
, M.Sc. Thesis Sharif University of Technology ; Khoei, Amir Reza (Supervisor) ; Jahanshahi, Mohsen (Co-Supervisor)
Abstract
In this thesis ،molecular dynamics simulation of structural and mechanical properties of pure aluminium and copper crystals as well as of the alloyed crystals including 10%,30%,50%,70% and 90% aluminium alloyed have been investigated using two various all-atom and coarse-grained models. Molecular dynamics simulations calculate the realistic behavior of the system and then use them in order to calculate the time average properties of the system. Embedded atom method (eam) and the numerical iterative Boltzmann Inversion method are employed to describe the interaction between atoms. The results are then compared with coarse-grained model. The demonstrated peaks in the radial distribution...
Compaction simulation of crystalline nano-powders under cold compaction process with molecular dynamics analysis
, Article Powder Technology ; Volume 373 , August , 2020 , Pages 741-753 ; Sameti, A. R ; Mofatteh, H ; Sharif University of Technology
Elsevier B. V
2020
Abstract
In this paper, the uniaxial cold compaction process of metal nano-powders is numerically analyzed through the Molecular Dynamics (MD) method. The nano-powders consist of nickel and aluminum nano-particles in the pure and mixed forms with distinctive contributions. The numerical simulation is performed using the different number of nano-particles, mixing ratios of Ni and Al nano-particles, compaction velocities, and ambient temperatures in the canonical ensemble until the full-dense condition is achieved. In the MD analysis, the inter-atomic interaction between metal nano-particles is modeled by the many-body EAM potential, and the interaction between frictionless rigid die-walls and metal...