Nanomechanics of carbon nanotubes creep, inter-tubular friction, and their interactions with graphene oxide

Carbon nanotubes (CNTs) are of great interest for load-bearing applications because of their excellent mechanical properties. While much effort has been made in the last decade in order to address problems that obscure the applications of CNTs with their remarkable properties fully exploited from b...

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Main Author: Yang, Tianyi
Other Authors: Liao Kin
Format: Theses and Dissertations
Language:English
Published: 2013
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Online Access:https://hdl.handle.net/10356/51095
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-510952023-03-03T15:57:52Z Nanomechanics of carbon nanotubes creep, inter-tubular friction, and their interactions with graphene oxide Yang, Tianyi Liao Kin School of Chemical and Biomedical Engineering DRNTU::Engineering Carbon nanotubes (CNTs) are of great interest for load-bearing applications because of their excellent mechanical properties. While much effort has been made in the last decade in order to address problems that obscure the applications of CNTs with their remarkable properties fully exploited from both experimental and theoretical perspectives, some fundamental issues regarding the nanomechanical behavior of individual CNTs at noncritical stress, the interaction between CNTs in their assembled forms and, along with the development of a method for effectively dispersing CNTs in aqueous and polymer media with their intrinsic properties retained are far from being settled. In this study, we first focus on probing the fracture mechanisms of CNTs creep using classical molecular dynamics (MD) and nudged elastic band (NEB) methods. The long-timescale microstructural evolution of CNTs at relatively low external stress is modeled by dividing the continuous process into a series of successive discrete transitions between metastable states. Our results indicate that there exist bifurcation states of the failure mechanism in armchair CNT: brittle-type fracture dominates the fracture if external stress exceeds 42.2 GPa for a (8, 8) CNT; alternatively, plastic deformation caused by the nucleation and diffusion of a specific type of defects, 5|7 dislocations, takes place, leads to the necking of the CNT before eventual fracture. Since the time-dependent behavior in CNT is only meaningfully characterized in engineering applications by deformation rate, and the relevant quantities that require sampling over a time dimension too large for atomistic simulation to reach, we adopt the concept from kinetic fracture theory. DOCTOR OF PHILOSOPHY (SCBE) 2013-01-09T04:36:44Z 2013-01-09T04:36:44Z 2012 2012 Thesis Yang, T. (2012). Nanomechanics of carbon nanotubes creep, inter-tubular friction, and their interactions with graphene oxide. Doctoral thesis, Nanyang Technological University, Singapore. https://hdl.handle.net/10356/51095 10.32657/10356/51095 en 220 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic DRNTU::Engineering
spellingShingle DRNTU::Engineering
Yang, Tianyi
Nanomechanics of carbon nanotubes creep, inter-tubular friction, and their interactions with graphene oxide
description Carbon nanotubes (CNTs) are of great interest for load-bearing applications because of their excellent mechanical properties. While much effort has been made in the last decade in order to address problems that obscure the applications of CNTs with their remarkable properties fully exploited from both experimental and theoretical perspectives, some fundamental issues regarding the nanomechanical behavior of individual CNTs at noncritical stress, the interaction between CNTs in their assembled forms and, along with the development of a method for effectively dispersing CNTs in aqueous and polymer media with their intrinsic properties retained are far from being settled. In this study, we first focus on probing the fracture mechanisms of CNTs creep using classical molecular dynamics (MD) and nudged elastic band (NEB) methods. The long-timescale microstructural evolution of CNTs at relatively low external stress is modeled by dividing the continuous process into a series of successive discrete transitions between metastable states. Our results indicate that there exist bifurcation states of the failure mechanism in armchair CNT: brittle-type fracture dominates the fracture if external stress exceeds 42.2 GPa for a (8, 8) CNT; alternatively, plastic deformation caused by the nucleation and diffusion of a specific type of defects, 5|7 dislocations, takes place, leads to the necking of the CNT before eventual fracture. Since the time-dependent behavior in CNT is only meaningfully characterized in engineering applications by deformation rate, and the relevant quantities that require sampling over a time dimension too large for atomistic simulation to reach, we adopt the concept from kinetic fracture theory.
author2 Liao Kin
author_facet Liao Kin
Yang, Tianyi
format Theses and Dissertations
author Yang, Tianyi
author_sort Yang, Tianyi
title Nanomechanics of carbon nanotubes creep, inter-tubular friction, and their interactions with graphene oxide
title_short Nanomechanics of carbon nanotubes creep, inter-tubular friction, and their interactions with graphene oxide
title_full Nanomechanics of carbon nanotubes creep, inter-tubular friction, and their interactions with graphene oxide
title_fullStr Nanomechanics of carbon nanotubes creep, inter-tubular friction, and their interactions with graphene oxide
title_full_unstemmed Nanomechanics of carbon nanotubes creep, inter-tubular friction, and their interactions with graphene oxide
title_sort nanomechanics of carbon nanotubes creep, inter-tubular friction, and their interactions with graphene oxide
publishDate 2013
url https://hdl.handle.net/10356/51095
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