scholarly journals Equivalent beam model of single walled carbon nanotube with imperfections

Author(s):  
Marino Brčić ◽  
Marko Čanađija ◽  
Josip Brnić
Author(s):  
H Ramezannejad Azarboni ◽  
SA Edalatpanah

In the studies of the dynamic response of carbon nanotubes, the stability, predictable, and unpredictable chaotic vibrations are fundamental characteristics. In this paper, we investigate the chaotic and periodic vibrations of a single-walled carbon nanotube resting on the viscoelastic foundation, based on the nonlocal Euler–Bernoulli beam model. It is assumed that the single-walled carbon nanotube is subjected to an external harmonic excitation. The axial thermomagnetic field and the surface effect on the governing equation of single-walled carbon nanotube are taken into account. We also solve the nonlinear governing equation by using the Galerkin decomposition method along with the fourth-order Rung–Kutta numerical integration scheme. Furthermore, we analyze the effects of amplitude and frequency of excitation on the formation of chaotic and periodic regions using bifurcation diagrams and largest Lyapunov exponents. Moreover, we present the phase portrait, Poincare maps, and time history to observe the periodic and chaotic responses of the system. The results show that the nonlinear dynamic response of single-walled carbon nanotube is much more sensitive to both amplitude and frequency of excitation.


2021 ◽  
Vol 37 ◽  
pp. 616-635
Author(s):  
Yu-Chi Su ◽  
Tse-Yu Cho

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.


Author(s):  
Demetris Pentaras ◽  
Isaac Elishakoff

The dynamic deflections of geometrically different single-walled carbon nanotubes are determined under various high-velocity impacts and for different positions at which ballistic impact is applied. Elastic beam model is applied to study the dynamic deflection of single-walled carbon nanotubes for two cases of boundary conditions, namely to clamped–clamped and clamped-free single-walled carbon nanotubes. Moreover, we examine the relationship between the single-walled carbon nanotube radius, the relative position at which the ballistic impact takes place, the speed of the object (e.g., bullet) that strikes the nanotube, and the deflection of the nanotube for a specific bullet size and shape as was used by recent study in the literature.


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