Wave propagation in fluid-filled multi-walled carbon nanotubes embedded in elastic matrix

This paper reports the result of an investigation into the wave propagation in a fluid-filled multi-walled carbon nanotubes embedded in elastic matrix, where multi-walled carbon nanotubes are considered as a multiple concentric shell coupled together through the van der Waals forces between two adjacent tubes, the surrounding matrix is considered as a spring element defined by the Winkler model, and a fluid loading term is induced by the presence of the fluid acoustic field in the innertube of multi-walled carbon nanotubes. Characteristics of wave propagation in a fluid-filled multi-walled carbon nanotubes are described through numerical examples considered the effect of matrix stiffness, van der Waals force and fluid velocity. The results obtained show that wave propagation in a fluid-filled carbon nanotubes embedded in elastic matrix exists some critical frequencies at which the velocity of wave drops dramatically and some cut-off frequencies before which the corresponding wave modes does not appear; the critical/cut-off frequency increases with the increase of matrix stiffness, and the influence of matrix is little on wave velocity in other frequency regions; there exists corresponding critical wave velocities for different wave modes when the effect of fluid velocity is considered. On the other hand, an approximate method is presented to effectively solve the wave propagation in a fluid-filled multi-walled carbon nanotubes with larger layers. This investigation may give a useful help in applications of nano-drive technology and nanopipes for conveying fluid.