Influence of structural imperfections—twisting and distortion—on the vibrational behavior of carbon nanotubes

2016 ◽  
Vol 230 (4) ◽  
pp. 222-230
Author(s):  
Sadegh Imani Yengejeh ◽  
Andreas Öchsner
Keyword(s):  
Carbon Nanotubes ◽  
Natural Frequencies ◽  
Longitudinal Axis ◽  
Free Boundary Conditions ◽  
Vibrational Behavior ◽  
Lower Natural Frequency ◽  
Twisting Angle ◽  
Structural Imperfections ◽  
Radial Axis ◽  
Structure Of Carbon Nanotubes

Several types of carbon nanotubes in their perfect and imperfect form were simulated, and their vibrational behavior was studied by performing computational examinations with fixed-free boundary conditions. Both computational and analytical results were compared in the case of perfect tubes. Afterward, three kinds of imperfections, that is, twisting angle, z-distortion along the longitudinal axis and xy-distortion along the radial axis, were introduced to the structure of perfect carbon nanotubes, and the natural frequencies of imperfect carbon nanotubes were numerically evaluated and compared with the behavior of the perfect ones. It was concluded that the existence of any type of imperfection in the structure of carbon nanotubes leads to a lower natural frequency and, as a result, lower vibrational stability. However, this trend was more visible for the carbon nanotubes with higher chirality.

scholarly journals Identification of Corrosion on a Hollow Tube Using Vibration

2014 ◽  
Vol 564 ◽  
pp. 176-181
Author(s):  
S.T. Cheng ◽  
Nawal Aswan Abdul Jalil ◽  
Zamir A. Zulkefli
Keyword(s):  
Free Boundary ◽  
Boundary Conditions ◽  
Natural Frequency ◽  
Impact Loading ◽  
Structural Damage ◽  
Natural Frequencies ◽  
Localized Corrosion ◽  
Free Boundary Conditions ◽  
The Impact ◽  
Impact Vibration

Vibration based technique have so far been focused on the identification of structural damage. However, not many studies have been conducted on the corrosion identification on pipes. The objective of this paper is to identify corrosion on pipes from vibration measurements. A hollow pipe, 500 mm in length with 63.5 mm in diameter was subjected to impact loading using an impact hammer to identify the natural frequency of the tube in two conditions i) without any corrosion and ii) with an induced localized 40 mm by 40 mm corrosion at the middle of the pipe. The shift of natural frequencies of the structures under free boundary conditions was examined for each node of excitation. The results showed that there is a shift in natural frequency of the pipe, between 3 and 4 Hz near to the corrosion area. It can suggested that that the impact vibration is capable of identifying of localized corrosion on a hollow tube.

The hrem observation of cross-sectional structure of carbon nanotubes

1997 ◽  
Vol 58 (11) ◽  
pp. 1887-1892 ◽  
Author(s):  
S.Q. Feng ◽  
D.P. Yu ◽  
G. Hub ◽  
X.F. Zhang ◽  
Z. Zhang
Keyword(s):  
Carbon Nanotubes ◽  
Cross Sectional ◽  
Sectional Structure ◽  
Structure Of Carbon Nanotubes

scholarly journals Effect of Mo in Co-Mo/MgO catalysts on the synthesis yield and structure of carbon nanotubes

2009 ◽  
Vol 117 (1365) ◽  
pp. 654-658 ◽  
Author(s):  
Masataka BABA ◽  
Hideaki SANO ◽  
Guo-Bin ZHENG ◽  
Yasuo UCHIYAMA
Keyword(s):  
Carbon Nanotubes ◽  
Synthesis Yield ◽  
Structure Of Carbon Nanotubes

scholarly journals An investigation into the free vibrations of carbon nanotubes using analytical and finite element methods

2021 ◽  
Author(s):  
Ishan Ali Khan
Keyword(s):  
Carbon Nanotubes ◽  
Finite Element ◽  
Eigenvalue Problem ◽  
Natural Frequencies ◽  
Nonlinear Eigenvalue Problem ◽  
Dynamic Stiffness ◽  
Free Vibrations ◽  
Mode Shapes ◽  
Wide Range ◽  
Walled Cnts

Since their discovery, immense attention has been given to carbon nanotubes (CNTs), due to their exceptional thermal, electronic and mechanical properties and, therefore, the wide range of applications in which they are, or can be potentially, employed. Hence, it is important that all the properties of carbon nanotubes are studied extensively. This thesis studies the vibrational frequencies of double-walled and triple-walled CNTs, with and without an elastic medium surrounding them, by using Finite Element Method (FEM) and Dynamic Stiffness Matrix (DSM) formulations, considering them as Euler-Bernoulli beams coupled with van der Waals interaction forces. For FEM modelling, the linear eigenvalue problem is obtained using Galerkin weighted residual approach. The natural frequencies and mode shapes are derived from eigenvalues and eigenvectors, respectively. For DSM formulation of double-walled CNTs, a nonlinear eigenvalue problem is obtained by enforcing displacement and load end conditions to the exact solution of single equation achieved by combining the coupled governing equations. The natural frequencies are obtained using Wittrick-Williams algorithm. FEM formulation is also applied to both double and triple-walled CNTs modelled as nonlocal Euler-Bernoulli beam. The natural frequencies obtained for all the cases, are in agreement with the values provided in literature.

Structure of carbon nanotubes probed by local and global probes

Carbon ◽  
2002 ◽  
Vol 40 (10) ◽  
pp. 1635-1648 ◽  
Author(s):  
Ph. Lambin ◽  
A. Loiseau ◽  
C. Culot ◽  
L.P. Biró
Keyword(s):  
Carbon Nanotubes ◽  
Structure Of Carbon Nanotubes
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