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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 18:16 |
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Conference: Bucharest University Faculty of Physics 2014 Meeting
Section: Atomic and Molecular Physics; Astrophysics
Title:
Atomistic models of localized elastic-plastic deformations in carbon nanotube
Authors:
G.KOSA(1), M.BERCU(2), V.V.GRECU(2)
Affiliation:
1) Root 66 – Brasov – Romania
2) University of Bucharest,Faculty of Physics,Bucharest-Magurele,Romania
E-mail
mircea_bercu@yahoo.com
Keywords:
SWCNT, molecular dynamics, Morse carbon-carbon potential
Abstract:
Deformation at constant rate of a carbon nanotube is investigated according to its initial elastic response up to plastic and flow behaviour. The force acting to elongate the bridged SWCNT is applied at one end, the other being fixed. The atomistic models calculations of 2200 - 5200 atoms are based on molecular dynamics using adapted Morse carbon-carbon potential. The simulations are assumed only for fast processes considered relative to those associated to large scale of atomic relaxation and defect formation. The deformation rate is considered in between 0.5 A/ps and 3.0 A/ps. This study investigates the transition from nano-tube structure to atomic wire, done by non-uniform distribution of strain, generated especially during reflections of the longitudinal deformation waves at the ends of SWCNT. This process takes place after the initiation of non-linear deformation regime, being triggered locally by transverse compression of the nanotube. The calculations reveal the frequency decay of the excited longitudinal vibrations modes and the decrease of the deformation wave velocity during its propagation along the carbon nanotube. The simulation starts at the initiation of SWCNT deformation up to its disruption. Strain localization become more evident at high rate of nanotube asymmetric elongation, producing an increasing heterogeneity when it reaches the plastic deformation stage.
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