Nonlinear free vibration of double walled carbon nanotubes by using describing function method with multiple trial functions

In this paper, nonlinear free vibration of double walled carbon nanotubes (DWCNTs) embedded in an elastic medium with geometric nonlinearity and interlayer van der Waals force nonlinearity are studied. The motion of the DWCNT is represented by multiple eigenfunctions of the linear system which are referred as trial functions. Describing function method (DFM) is employed in order to represent the nonlinear forces as a multiplication of a nonlinear stiffness matrix and a displacement vector, which made it possible to identify when it is necessary to consider multiple trial functions. The results revealed that it is important to consider multiple trial functions, especially in case of out-of-phase vibrations of DWCNTs with interlayer van der Waals force nonlinearity. The effects of number of trial functions and medium stiffness on the free vibration of DWCNTs are investigated. It is observed that utilizing multiple trial functions made it possible to detect different vibration modes occurring at a single vibration frequency.


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Nonlinear free vibration analysis of curved double-walled carbon nanotubes (DWNTs) embedded in an elastic medium is studied in this study. Nonlinearities considered are due to large deflection of carbon nanotubes (geometric nonlinearity) and nonlinear interlayer van der Waals forces between inner and outer tubes. The differential quadrature method (DQM) is utilized to discretize the partial differential equations of motion in spatial domain, which resulted in a nonlinear set of algebraic equations of motion...
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In this thesis, effects of Geometric, initial curvature, and van der Waals (vdW) interlayer force nonlinearities on the variation of nonlinear natural frequency of Carbon Nanotubes (CNTs) are investigated in detail throughout several case studies. Galerkin method with a single trial function, which is the eigenfunction of the linear system, is widely used in literature in studying nonlinear vibrations of CNTs. However, eigenfunctions of the nonlinear systems can be significantly different than the eigenfunc...
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Citation Formats
E. Ciğeroğlu, “Nonlinear free vibration of double walled carbon nanotubes by using describing function method with multiple trial functions,” PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, pp. 160–173, 2012, Accessed: 00, 2020. [Online]. Available: