Faculty of Mechanical Engineering, 2Institute of Nanoscience & Nanotechnology, University of Kashan, Kashan, Islamic Republic of Iran
In the present study, dynamic stability of double-walled boron nitride nanotubes (DWBNNTs) including surface stress effects is investigated based on Gurtin-Murdoch continuum theory. Nonlocal piezoelasticity is incorporated into shell theory to develop non-classical model for DWBNNT. The effects of van der Waals (vdW) forces, viscose fluid passes through the inner nanotube and visco-Pasternak medium are evaluated. Fluid-DWBNNT interaction is evaluated considering slip boundary condition and bulk viscosity. Hamilton’s principle is utilized to derive governing equations with regard to von Kármán geometric nonlinearity. Finally incremental harmonic balance method (IHBM) indicates the dynamic instability region (DIR) of DWBNNT.
The detailed parametric study is conducted, focusing on the combined effects of the surface parameters, nonlocality, fluid velocity, Knudsen number, thermal changes, vdW forces and surrounding medium on the DIR of DWBNNT. Numerical results indicate that considering surface stress effect shifts the DIR to higher frequency zone.