Mechanics of Ellipsoidal Carbon Onions Inside Multiwalled Carbon Nanotubes

2012 ◽  
Vol 3 (1) ◽  
Author(s):  
F. Sadeghi ◽  
R. Ansari
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Oscillation Frequency ◽  
Direct Method ◽  
Van Der Waals ◽  
Oscillatory Behavior ◽  
Van Der Waals Interactions ◽  
Continuum Approximation ◽  
Multiwalled Carbon ◽  
Carbon Onions

On the basis of the continuum approximation along with Lennard–Jones potential function, new semi-analytical expressions are presented to evaluate the van der Waals interactions between an ellipsoidal fullerene and a semi-infinite single-walled carbon nanotube. Using direct method, these expressions are also extended to model ellipsoidal carbon onions inside multiwalled carbon nanotubes. In addition, acceptance and suction energies which are two noticeable issues for medical applications such as drug delivery are determined. Neglecting the frictional effects and by imposing some simplifying assumptions on the van der Waals interaction force, a simple formula is given to evaluate the oscillation frequency of ellipsoidal carbon onions inside multiwalled carbon nanotubes. Also, the effects of the number of tube shells and ellipsoidal carbon onion shells on the oscillatory behavior are examined. It is shown that there exists an optimal value for the number of tube shells beyond which the oscillation frequency remains unchanged.

Vibration Characteristics of Multiwalled Carbon Nanotubes Embedded in Elastic Media by a Nonlocal Elastic Shell Model

2007 ◽  
Vol 74 (6) ◽  
pp. 1087-1094 ◽  
Author(s):  
Renfu Li ◽  
George A. Kardomateas
Keyword(s):  
Carbon Nanotubes ◽  
Shell Model ◽  
Multiwalled Carbon Nanotubes ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Elastic Media ◽  
Small Length ◽  
Multiwalled Carbon ◽  
Resonant Frequencies ◽  
Length Scales

In this paper, the vibrational behavior of the multiwalled carbon nanotubes (MWCNTs) embedded in elastic media is investigated by a nonlocal shell model. The nonlocal shell model is formulated by considering the small length scales effects, the interaction of van der Waals forces between two adjacent tubes and the reaction from the surrounding media, and a set of governing equations of motion for the MWCNTs are accordingly derived. In contrast to the beam models in the literature, which would only predict the resonant frequencies of bending vibrational modes by taking the MWCNT as a whole beam, the current shell model can find the resonant frequencies of three modes being classified as radial, axial, and circumferential for each nanotube of a MWCNT. Big influences from the small length scales and the van der Waals’ forces are observed. Among these, noteworthy is the reduction in the radial frequencies due to the van der Waals’ force interaction between two adjacent nanotubes. The numerical results also show that when the spring constant k0 of the surrounding elastic medium reaches a certain value, the lowest resonant frequency of the double walled carbon nanotube drops dramatically.

Oscillation of C60 Fullerene in Carbon Nanotube Bundles

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
R. Ansari ◽  
F. Sadeghi ◽  
A. Alipour
Keyword(s):  
Carbon Nanotube ◽  
Potential Energy ◽  
Oscillation Frequency ◽  
Initial Conditions ◽  
Van Der Waals ◽  
Oscillatory Behavior ◽  
C60 Fullerene ◽  
Continuum Approximation ◽  
Geometrical Parameters ◽  
Energy Potential

This paper aims to present a thorough investigation into the mechanics of a C60 fullerene oscillating within the center of a carbon nanotube bundle. To model this nanoscale oscillator, a continuum approximation is used along with a classical Lennard–Jones potential function. Accordingly, new semianalytical expressions are given in terms of single integrals to evaluate van der Waals potential energy and interaction force between the two nanostructures. Neglecting the frictional effects and using the actual van der Waals force distribution, the equation of motion is directly solved. Furthermore, a new semianalytical formula is derived from the energy equation to determine the precise oscillation frequency. This new frequency formula has the advantage of incorporating the effects of initial conditions and geometrical parameters. This enables us to conduct a comprehensive study of the effects of significant system parameters on the oscillatory behavior. Based upon this study, the variation of oscillation frequency with geometrical parameters (length of tubes or number of tubes in bundle) and initial energy (potential energy plus kinetic energy) is shown.

scholarly journals Mechanical Characterization of Multiwalled Carbon Nanotubes: Numerical Simulation Study

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4283 ◽  
Author(s):  
Nataliya A. Sakharova ◽  
André F. G. Pereira ◽  
Jorge M. Antunes ◽  
José V. Fernandes
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Mechanical Characterization ◽  
Element Model ◽  
Van Der Waals Interactions ◽  
Multiwalled Carbon ◽  
Shear Moduli ◽  
Simplified Finite Element Model

The elastic properties of armchair and zigzag multiwalled carbon nanotubes were investigated under tensile, bending, and torsion loading conditions. A simplified finite element model of the multiwalled carbon nanotubes, without taking into account the van der Waals interactions between layers, was used to assess their tensile, bending, and torsional rigidities and, subsequently, Young’s and shear moduli. Relationships between the tensile rigidity and the squares of the diameters of the outer and inner layers in multiwalled carbon nanotubes, and between the bending and torsional rigidities with the fourth powers of the diameters of the outer and inner layers, were established. These relationships result in two consistent methods, one for assessment to the Young’s modulus of armchair and zigzag multiwalled carbon nanotubes, based on tensile and bending rigidities, and the other to evaluate shear modulus using tensile, bending, and torsional rigidities. This study provides a benchmark regarding the determination of the mechanical properties of nonchiral multiwalled carbon nanotubes by nanoscale continuum modeling approach.

scholarly journals Axial Stiffness of Multiwalled Carbon Nanotubes as a Function of the Number of Walls

2012 ◽  
Vol 57 (9) ◽  
pp. 933
Author(s):  
V. Zavalniuk
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Van Der Waals ◽  
Young Modulus ◽  
Axial Stiffness ◽  
Inverse Relation ◽  
Multiwalled Carbon ◽  
External Radius ◽  
Good Agreement

The axial stiffness of multiwalled carbon nanotubes (MWCNTs) is studied as a function of the number of walls and their parameters. It is demonstrated that the axial stiffness is determined only by several external shells (usually 3–5 and up to 15 for the extremely large nanotubes and high elongations) which is in good agreement with the experimentally observed inverse relation between the radius and the Young modulus (i.e., stiffness) of MWCNTs. Such behavior isa consequence of the van der Waals intershell interaction. An interpolating formula for the MWCNT's actual axial stiffness as a function of the external radius and the elongation of a tube is obtained.

Effect of Multiwalled Carbon Nanotubes On Mechanical Properties of Concrete

2012 ◽  
Vol 2 (6) ◽  
pp. 166-168 ◽  
Author(s):  
Dr.T.Ch.Madhavi Dr.T.Ch.Madhavi ◽  
◽  
Pavithra.P Pavithra.P ◽  
Sushmita Baban Singh Sushmita Baban Singh ◽  
S.B.Vamsi Raj S.B.Vamsi Raj ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Multiwalled Carbon
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