Nonlinear Behavior of Single Walled Carbon Nanotube Reinforced Aluminium Alloy Beam

This paper aims to analyze the nonlinear vibration of clamped-clamped buckled beams made of Aluminium alloy (Al-alloy) reinforced with uniformly dispersed Single Walled Carbon Nanotube (SWNT). The mean field homogenization technique is used to predict the effective material properties of the beams. The equation of motion governing the nonlinear behavior is solved using an exact method. The effects of various parameters including axial load, vibration amplitude, SWNT volume fraction, SWNT aspect ratio and beam slenderness ratio on the nonlinear frequency and on the phase trajectory plots for pre- and post-buckling states are studied.

Nonlinear Vibration of a Pre-Stressed Water-Filled Single-Walled Carbon Nanotube Using Shell Model

Nanomaterials ◽

10.3390/nano10050974 ◽

2020 ◽

Vol 10 (5) ◽

pp. 974

Author(s):

Mahmoud Mohamed Selim ◽

Awad Musa

Keyword(s):

Carbon Nanotube ◽

Nonlinear Vibration ◽

Shell Theory ◽

Analytical Formula ◽

Water System ◽

Nonlinear Frequency ◽

Nonlinear Parameters ◽

Lower Mode ◽

This paper is an attempt to study the nonlinear vibration of a pre-stressed single-walled carbon nanotube (SWCNT) with water-filled and simply supported ends. A new analytical formula is obtained for the nonlinear model based on the simplified Donnell’s shell theory. The effects of internal fluid on the coupling vibration of the SWCNT–water system are discussed in detail. Furthermore, the influence of the different nanotube thicknesses and radiuses on the nonlinear vibration frequencies is investigated according to the shell theory. Numerical calculations are done to show the effectiveness of the proposed schemes. The results show that the nonlinear frequency grew with the increasing nonlinear parameters (radius and thickness of nanotube). In addition, it is shown that the influence of the nonlinear parameters is greater at the lower mode in comparison with the higher mode for the same nanotube thickness and radius.

ASME 2012 Third International Conference on Micro/Nanoscale Heat and Mass Transfer ◽

Enhanced Thermal Conductivity of Water With Surfactant Encapsulated and Individualized Single-Walled Carbon Nanotube Dispersions

10.1115/mnhmt2012-75021 ◽

2012 ◽

Author(s):

S. Harish ◽

Kei Ishikawa ◽

Erik Einarsson ◽

Taiki Inoue ◽

Shohei Chiashi ◽

...

Keyword(s):

Thermal Conductivity ◽

Carbon Nanotube ◽

Effective Thermal Conductivity ◽

Volume Fraction ◽

Thermal Conductivity Enhancement ◽

Optical Absorption Spectroscopy ◽

Conductivity Enhancement ◽

Single Walled Carbon ◽

Higher Temperature

In the present work, the effective thermal conductivity of single walled carbon nanotube dispersions in water was investigated experimentally. Single-walled carbon nanotubes (SWNTs) were synthesized using the alcohol catalytic chemical vapour deposition method. The diameter distribution of the SWNTs was determined using resonance Raman spectroscopy. Sodium deoxycholate (SDC) was used as the surfactant to prepare the nanofluid dispersions. Photoluminescence excitation spectroscopy (PLE) reveals that majority of the nanotubes were highly individualized when SDC was employed as the surfactant. The nanofluid dispersions were further characterized using transmission electron microscopy, atomic force microscopy (AFM) and optical absorption spectroscopy (OAS). Thermal conductivity measurements were carried out using a transient hot wire technique. Nanotube loading of up to 0.3 vol% was used. Thermal conductivity enhancement was found to be dependent on nanotube volume fraction and temperature. At room temperature the thermal conductivity enhancement was found to be non-linear and a maximum enhancement of 13.8% was measured at 0.3 vol% loading. Effective thermal conductivity was increased to 51% at 333 K when the nanotube loading is 0.3 vol%. Classical macroscopic models fail to predict the measured thermal conductivity enhancement precisely. The possible mechanism for the enhancement observed is attributed to the percolation of nanotubes to form a three-dimensional structure. Indirect effects of Brownian motion may assist the formation of percolating networks at higher temperature thereby leading to further enhancements at higher temperature.

Effective Medium Calculations of the Electromagnetic Behavior of Single Walled Carbon Nanotube Composites

MRS Proceedings ◽

10.1557/proc-739-h7.42 ◽

2002 ◽

Vol 739 ◽

Cited By ~ 1

Author(s):

John W. Schultz ◽

Rick L. Moore

Keyword(s):

Carbon Nanotubes ◽

Carbon Nanotube ◽

Dielectric Properties ◽

Volume Fraction ◽

Metal Layer ◽

Effective Permittivity ◽

Effective Medium ◽

Dielectric Constants ◽

ABSTRACTDielectric properties of single walled carbon nanotube assemblies were calculated with an effective medium approximation at frequencies from 200 MHz to 200 GHz. The model treats the carbon nanotubes as layered cylinders, each with a core, a graphene layer and an outer layer, to investigate the dielectric properties of coated and filled nanotubes. The graphene and metal layer properties were modeled with a Drude approximation based on literature data. A generalized Bruggeman model was then used to determine the macroscopic behavior of the modified carbon nanotubes in a composite structure as a function of volume fraction, frequency, and aspect ratio. The depolarization factors in this model were scaled by the normalized effective permittivity to better account for percolation behavior. The model showed a wide variety of frequency dependent dielectric properties. Uncoated tubes were calculated to form highly conductive materials at volume fractions of just a few percent and metal-coated tubes enhanced the conductivity by an order of magnitude. Calculations of nanotubes with insulating coatings showed that high dielectric constants with moderate to low dielectric loss were possible.

Free vibration of a single-walled carbon nanotube based on the nonlocal Timoshenko beam model

Journal of Mechanics ◽

10.1093/jom/ufab028 ◽

2021 ◽

Vol 37 ◽

pp. 616-635

Author(s):

Yu-Chi Su ◽

Tse-Yu Cho

Keyword(s):

Carbon Nanotube ◽

Free Vibration ◽

Elastic Medium ◽

Timoshenko Beam ◽

Slenderness Ratio ◽

Mode Shapes ◽

Beam Model ◽

Timoshenko Beam Model ◽

Abstract Free vibration of a single-walled carbon nanotube (SWCNT) embedded in an elastic medium is studied on the basis of the nonlocal Timoshenko beam model. Influences of the slenderness ratios, the boundary conditions, the atomic structures and the stiffness of the embedded medium on the natural frequencies and mode shapes of SWCNT are examined. The nonlocal effect is significant for the higher modes of SWCNT with a small slenderness ratio embedded in a soft elastic medium, and it softens the SWCNT except for the fundamental frequency of the clamped–free SWCNT.