Exponential and harmonic forced torsional vibration of single-walled carbon nanotube in an elastic medium. (May 2020)

• Record Type: Journal Article
• Authors: Khosravi, Farshad; Hosseini, Seyyed Amirhosein; Norouzi, Hamid
• Is Part Of: Proceedings of the Institution of Mechanical Engineers. Volume 234:Number 10(2020)
• Page Start: 1928
• Page End: 1942
• Publication Date: 2020-05
• Subjects: Eringen's theory -- free vibration -- forced torsional vibration -- single-walled carbon nanotube -- elastic medium -- resonance behavior; Mechanical engineering -- Periodicals; 621.05
• DOI: 10.1177/0954406220903341
• Languages: English
• ISSNs: 0954-4062

Abstract

In this study, free torsional vibration and forced torsional vibration analysis under the time-dependent exponential and harmonic torsional loadings in single-walled carbon nanotube are investigated. The SWCNT is embedded in an elastic medium. Eringen's theory among the small-scale theories is selected. The nonlocal differential constitutive relation and corresponding boundary condition are derived via Hamilton's principle. Clamped–clamped boundary condition is utilized. The assumed modes method is employed for the dynamic torsional vibration in order to discretize the derived governing equations. The novelty of this work is devoted to the analysis of forced torsional vibration of a carbon nanotube embedded in an elastic medium under the various loadings. The angular displacement for the resonance frequency neglecting the elastic medium is illustrated. For the free analysis, the first three nondimensional natural frequencies with various small-scale parameters and stiffness of the elastic medium are calculated. The results are compared with another study for the first 10 mode numbers. The effects of the nonlocal parameter, length of carbon nanotube, stiffness of the elastic medium, thickness, time constant, and excitation frequency on the nondimensional and dimensional angular displacements are investigated, dynamically. For the greater values of the stiffness of the medium, the nonlocal parameter becomes negligible. When a time-dependent exponential torque is applied to the model, the angular displacement becomes greater and then lower by an increase in the value of the length, but the nondimensional angular displacement decreases continuously by increasing the value of the length under the time-dependent harmonic loading. Moreover, the angular displacement for a determined time becomes lower first and then becomes greater by increasing the time constant.