Wave propagation in fluid‐conveying nanotubes under multi‐physical fields based on non‐local higher‐order strain gradient model

Abstract

This work studies the wave propagation in embedded single-walled carbon nanotubes (CNTs) conveying fluid and placed in multi-physical fields based on the non-local higher-order strain gradient model with surface effect considered. The nanotubes are modelled as Timoshenko beams. Utilising Hamilton's principle, the governing equations of wave motion in CNTs are derived. The solution for the phase velocity of wave motion is obtained, which can not only consider the stiffness softening effect but also reflect the stiffness enhancement effect of scale parameter observed by experiments. The numerical simulations are conducted to compare the results on the basis of different order non-local strain gradient models. It is shown that the behaviours of wave propagation based on the non-local higher-order strain gradient models are quite different from those based on the classical continuum model. In addition, the scale and surface effects and influences of various external factors including inner flow, surrounding medium, temperature field, and magnetic field on the wave dispersion are investigated.