scholarly journals Buckling and Vibration of Carbon Nanotubes Embedded in Polyethylene Polymers

2012 ◽  
Vol 3 (2) ◽  
Author(s):  
Dai Shi ◽  
Quan Wang ◽  
Vijay K. Varadan ◽  
Wenhui Duan
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Molecular Mechanics ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Buckling Instability ◽  
Resonance Frequencies

The discovery of buckling instability and vibration of polyethylene (PE)/carbon nanotube (CNT) matrices is reported by molecular mechanics simulations. The buckling strains and the resonance frequencies are found to decrease with an increase in the number of polyethylene chains in the polyethylene/carbon nanotube matrices. The van der Waals forces between the polyethylene chains and the carbon nanotube in matrices are investigated to provide physical interpretations on the findings.

scholarly journals Buckling and Vibration of Carbon Nanotubes Embedded in Polyethylene Polymers

2011 ◽  
Vol 148-149 ◽  
pp. 1016-1020
Author(s):  
Dai Shi ◽  
Quan Wang
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Resonance Frequency ◽  
Molecular Mechanics ◽  
Dynamic Characteristics ◽  
Van Der Waals ◽  
High Strength ◽  
Van Der Waals Forces ◽  
Buckling Instability ◽  
Resonance Frequencies

The discovery of buckling instability and vibration of polyethylene/ carbon nanotube matrices is reported by molecular mechanics simulations. The research is aimed to acquire a high strength design of PE-CNT matrix with proper PE/CNT ratio as well as discovering the dynamic characteristics of the PE-CNT composites. The buckling strains and the resonance frequencies are found to decrease with an increase in the number of polyethylene chains in the polyethylene/carbon nanotube matrices. Van der Waals forces are collected to explain the relation of the PE chains to the buckling strain and the resonance frequency of the composites.

Investigation of the Fundamental Frequency of Double Walled Carbon Nanotubes Using Molecular Mechanics Approach by an Averaging Van Der Waals Forces Modeling

2011 ◽  
Author(s):  
Ehsan Asadi ◽  
Ali Karimzade ◽  
Mehrdad Farid
Keyword(s):  
Carbon Nanotubes ◽  
Aspect Ratio ◽  
Molecular Mechanics ◽  
Fundamental Frequency ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Covalent Bonds ◽  
Fundamental Frequencies ◽  
Double Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Carbon nanotubes have received a lot of attention since their introduction in 1991 because of novel properties that show substantial promises for use in many applications. Their usage depends on the strength of our knowledge of their properties. In this work, molecular mechanics approach is used to study the mechanical properties of multi-wall carbon nanotubes. In particular this paper investigates fundamental frequency of double walled carbon nanotubes. Carbon nanotubes are big and long molecules that can be regarded as mechanical structures. In modeling of multi-walled carbon nanotubes, two distinct atomic bonds are required to be modeled, i.e. covalent bonds between the neighboring carbon atoms in the same layer and Van der Waals bonds between close atoms in neighboring layers. In this approach, for modeling of each wall; covalent bonds are modeled by beam joints such that atoms are considered to be concentrated masses at the ends. Interactions of neighboring walls that are mainly due to Van der Waals forces are treated to be truss rods in modeling. The most challenging aspect of modeling is to define truss rod properties as they are highly nonlinear. We utilized an averaging method for finding truss rod properties. Finite Element Method is employed to obtain Fundamental frequencies. Results are compared to available researches and a close agreement is observed. Results indicate that by increasing aspect ratio, fundamental frequency of double walled nanotubes decrease. In addition, double walled carbon nanotubes have higher fundamental frequencies at clamp-clamp in comparison to clamp-free condition; however, this difference becomes negligible as aspect ratio increases.

Frequency Response of Parametric Resonance of Double Wall Carbon Nanotube Under Electrostatic Actuation

2017 ◽  
Author(s):  
Dumitru I. Caruntu ◽  
Ezequiel Juarez
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Parametric Resonance ◽  
Multiple Scales ◽  
Van Der Waals ◽  
Nonlinear Behavior ◽  
Van Der Waals Forces ◽  
Electrostatic Actuation ◽  
Beam Model ◽  
Electrostatically Actuated

This paper deals with electrostatically actuated Double Walled Carbon Nanotubes (DWCNT) cantilevered resonators. The governing equations for the motion of the DWCNT are derived through Euler-Bernoulli beam model assumptions that account for inertial and viscoelastic effects. The DWCNT is a specific type of multi-walled carbon nanotube (MWCNT) that is comprised of two coaxially concentric carbon nanotubes. Electrostatic, damping, and intertube van der Waals forces act on the outer tube of the DWCNT, while only intertube van der Waals force acts on the inner tube. A soft AC voltage provides the electrostatic actuation. The nonlinear behavior and phenomena in the system are provided by the electrostatic and intertube van der Waals forces. The DWCNT is subjected to nonlinear parametric dynamics. The Method of Multiple Scales (MMS) is employed to investigate the system under soft excitations and/or weak nonlinearities. The frequency-amplitude response is found in the case of parametric resonance. The resulting nonlinear dynamic behavior is important to improve DWCNT resonator sensitivity in the application of mass sensing.

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.

On Primary Resonance of Electrostatically Actuated Double Walled Carbon Nanotube Cantilever Biosensors

2015 ◽  
Author(s):  
Dumitru I. Caruntu ◽  
Ezequiel Juarez
Keyword(s):  
Carbon Nanotubes ◽  
Multiple Scales ◽  
Van Der Waals ◽  
Primary Resonance ◽  
Harmonic Balance Method ◽  
Van Der Waals Forces ◽  
Mass Sensing ◽  
Electrostatically Actuated ◽  
Double Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

This paper investigates electrostatically actuated Double Walled Carbon Nanotubes (DWCNT) cantilever biosensors using the Method of Multiple Scales (MMS) and the Harmonic Balance Method (HBM). Forces acting on the outer tube of the DWCNT are electrostatic, damping, and van der Waals, while only van der Waals acts on the inner tube. The electrostatic actuation is provided by a soft AC voltage. Van der Waals forces are present between the carbon nanotubes, coupling the deflections of the tubes; herein, for modal coordinate transformation, only the linear term of the van der Waals force will be considered. The nonlinearity of the motion is produced by the electrostatic and van der Waals forces. The DWCNT undergoes nonlinear parametric dynamics. MMS is employed to investigate the system under soft excitations and/or weak nonlinearities. The frequency-amplitude response is found in the case of primary resonance. DWCNTs are modelled after the Euler-Bernoulli cantilever beam. The expected nonlinear dynamic behavior is important to improve DWCNT resonator sensitivity in the application of mass sensing.

scholarly journals Pull-in instability study of carbon nanotube tweezers under the influence of van der Waals forces

2004 ◽  
Vol 14 (8) ◽  
pp. 1119-1125 ◽  
Author(s):  
Gen-Wei Wang ◽  
Yin Zhang ◽  
Ya-Pu Zhao ◽  
Gui-Tong Yang
Keyword(s):  
Carbon Nanotube ◽  
Van Der Waals ◽  
Van Der Waals Forces
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