DYNAMIC ANALYSIS OF FLUID-CONVEYING CARBON NANOPIPES USING A NOVEL SPECTRAL ELEMENT FORMULATION

Abstract

The dynamic behaviour of fluid-conveying double-walled carbon nanotubes (DWCNTs) is important in nanoscale fluid-transport systems because fluid–structure interaction, interwall forces, size-dependent effects and environmental loading can significantly influence their vibration characteristics. Therefore, this paper aims to control the dynamic vibration of flowing fluid through DWCNT systems to enhance their integrity and reliability. However, this study develops a spectral-element formulation for the dynamic analysis of a water-conveying double-walled nano-pipe subjected to an elastic foundation. The formulation incorporates Eringen’s nonlocal elasticity theory, linear van der Waals interaction between the inner and outer walls, Knudsen-number-dependent slip flow, Pasternak elastic foundation, and linear and nonlinear Winkler foundation effects. The governing equation is derived using Hamilton’s principle and transformed into a frequency-domain spectral-element formulation from which the dynamic response and natural frequencies are obtained. Numerical simulations examine how the major governing parameters influence the nano-pipe's vibration characteristics. The results show that increasing the Pasternak and Winkler foundation stiffnesses increases the natural frequency while reducing the displacement amplitude and suppressing sustained oscillations. Similarly, increasing the van der Waals interaction strength and geometric length also reduces the vibration amplitudes and enhances the dynamic stability of the double-walled system. The combined variation of van der Waals interaction and Knudsen number produces a gradual increase in the first natural frequency from approximately 32.45 GHz to 32.95 GHz within the investigated parameter range. In contrast, increasing the Knudsen number also increases the displacement amplitude, although the oscillations progressively decay with time. These results demonstrate that interwall interaction, nanoscale fluid-flow effects, geometric length and foundation stiffness are important in predicting and controlling the dynamic behaviour of fluid-conveying DWCNTs. The proposed spectral-element framework provides an efficient computational approach for dynamically assessing and designing reliable nanoscale water-transport systems.