VIBRATIONS OF FLUID-CONVEYING FUNCTIONALLY GRADED NANOTUBES BASED ON THE REFINED BEAM THEORY IN VARYING TEMPERATURE CONDITIONS

Abstract

This paper investigates a model of a fluid-conveying functionally graded (FG) nanotube, based on the refined beam theory in the framework of the nonlocal strain gradient theory. Material properties change smoothly in the radial direction of the nanotube, based on the power-law distribution. Equations of motion are obtained by using Hamilton’s principle, while eigenvalues are obtained through Galerkin’s method. The influence of the temperature change was noticeable. Two types of temperature changes were considered, uniform and linear temperature rise. The paper deals with the effect of the presence of fluid in the nanotube, which is being conveyed through the nanotube and the effect of the temperature change on the change of natural frequency. Also, the critical fluid velocity and critical thermal buckling load are considered. The influence of the nonlocal and strain gradient parameter on the natural frequency, critical fluid velocity and thermal load should not be neglected. Finally, as mentioned above, the material of the nanotube model depends on the power-law distribution, so the effect of the power-law exponent on the natural frequency and critical fluid velocity is observed.