Nanomechanics of carbon nanotubes based nanoscale devices

Owing to their exceptional mechanical properties, carbon nanotubes have recently emerged as promising candidates to construct nearly wear-less nanomechanical devices that can operate at ultra-high gigahertz frequencies. In this work, we specifically focus on simple machine components such as linear...

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Main Author: Shenai, Prathamesh Mahesh.
Other Authors: Zhao Yang
Format: Theses and Dissertations
Language:English
Published: 2013
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Online Access:http://hdl.handle.net/10356/52488
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-524882023-03-04T16:36:44Z Nanomechanics of carbon nanotubes based nanoscale devices Shenai, Prathamesh Mahesh. Zhao Yang School of Materials Science & Engineering DRNTU::Engineering::Materials::Nanostructured materials DRNTU::Engineering::Nanotechnology DRNTU::Engineering::Mechanical engineering::Mechanics and dynamics Owing to their exceptional mechanical properties, carbon nanotubes have recently emerged as promising candidates to construct nearly wear-less nanomechanical devices that can operate at ultra-high gigahertz frequencies. In this work, we specifically focus on simple machine components such as linear nano-oscillators and rotational nanobearings based on double-walled carbon nanotubes (DWNTs) and investigate those with the help of molecular dynamics (MD) simulations. This thesis aims at a comprehensive study of nanomechanics of DWNTs based nanomachines along three major aspects - performance, driving mechanisms and non-linear dynamics. We have first carried out an extensive study of factors affecting the performance of rotational nanobearings. An interesting operational regime for a short-sleeved rotational bearing constructed with (4,4)/(9,9) DWNT exhibiting a peculiar dependence on the rotational speed was uncovered. When initiated with an intermediately high angular speed, such bearing may undergo energy dissipation and enter stable operational regimes at certain specific lower angular velocity ranges. We successfully identified the energy transfer pathways between different modes that may lead to such energy dissipation. The translational motion of the sleeve was found to serve as the channeling mode that funnels a part of its rotational kinetic energy to the dissipative modes such as wavy modes of the long inner tube. As the axial translation comes to a halt, the decay channel gets closed leading to stable rotation. We then used this principle of the energy leakage channel blocking to propose a novel design scheme of a rotational nanobearing with improved performance. In the proposed structure called the `flanged nanobearing', a DWNT is structurally modified by connecting to both of its ends, another DWNT with slightly larger tube diameters. The flanged nanobearing near-completely inhibits the axial sliding of the rotor thereby resulting in an improved bearing operation at both the high angular velocity and at high temperature regimes. Doctor of Philosophy (MSE) 2013-05-09T06:24:38Z 2013-05-09T06:24:38Z 2013 2013 Thesis http://hdl.handle.net/10356/52488 en 155 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::Materials::Nanostructured materials
DRNTU::Engineering::Nanotechnology
DRNTU::Engineering::Mechanical engineering::Mechanics and dynamics
spellingShingle DRNTU::Engineering::Materials::Nanostructured materials
DRNTU::Engineering::Nanotechnology
DRNTU::Engineering::Mechanical engineering::Mechanics and dynamics
Shenai, Prathamesh Mahesh.
Nanomechanics of carbon nanotubes based nanoscale devices
description Owing to their exceptional mechanical properties, carbon nanotubes have recently emerged as promising candidates to construct nearly wear-less nanomechanical devices that can operate at ultra-high gigahertz frequencies. In this work, we specifically focus on simple machine components such as linear nano-oscillators and rotational nanobearings based on double-walled carbon nanotubes (DWNTs) and investigate those with the help of molecular dynamics (MD) simulations. This thesis aims at a comprehensive study of nanomechanics of DWNTs based nanomachines along three major aspects - performance, driving mechanisms and non-linear dynamics. We have first carried out an extensive study of factors affecting the performance of rotational nanobearings. An interesting operational regime for a short-sleeved rotational bearing constructed with (4,4)/(9,9) DWNT exhibiting a peculiar dependence on the rotational speed was uncovered. When initiated with an intermediately high angular speed, such bearing may undergo energy dissipation and enter stable operational regimes at certain specific lower angular velocity ranges. We successfully identified the energy transfer pathways between different modes that may lead to such energy dissipation. The translational motion of the sleeve was found to serve as the channeling mode that funnels a part of its rotational kinetic energy to the dissipative modes such as wavy modes of the long inner tube. As the axial translation comes to a halt, the decay channel gets closed leading to stable rotation. We then used this principle of the energy leakage channel blocking to propose a novel design scheme of a rotational nanobearing with improved performance. In the proposed structure called the `flanged nanobearing', a DWNT is structurally modified by connecting to both of its ends, another DWNT with slightly larger tube diameters. The flanged nanobearing near-completely inhibits the axial sliding of the rotor thereby resulting in an improved bearing operation at both the high angular velocity and at high temperature regimes.
author2 Zhao Yang
author_facet Zhao Yang
Shenai, Prathamesh Mahesh.
format Theses and Dissertations
author Shenai, Prathamesh Mahesh.
author_sort Shenai, Prathamesh Mahesh.
title Nanomechanics of carbon nanotubes based nanoscale devices
title_short Nanomechanics of carbon nanotubes based nanoscale devices
title_full Nanomechanics of carbon nanotubes based nanoscale devices
title_fullStr Nanomechanics of carbon nanotubes based nanoscale devices
title_full_unstemmed Nanomechanics of carbon nanotubes based nanoscale devices
title_sort nanomechanics of carbon nanotubes based nanoscale devices
publishDate 2013
url http://hdl.handle.net/10356/52488
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