On the stability of spinning thin-walled porous beams

In the current study, the stability analysis of functionally graded (FG) thin-walled porous beams reinforced by nanocomposite graphene platelets (GPLs) under compressive axial load is investigated. It is assumed that the thin-walled porous beam is spinning along its longitudinal axis and both symmetric and asymmetric distributions of porosity are considered. Furthermore, the GPLs are distributed thorough the thickness direction both uniformly and non-uniformly. The effective material properties such as Young's modulus, mass density and Poisson's ratio of the porous beams are computed based on the Halpin-Tsai micromechanics model and the rule of mixture. The extended Hamilton's principle is utilized to establish the governing equations and they are discretized by the extended Galerkin method (EGM). The effects of various parameters such as GPL porous distribution patterns, GPL weight fraction, geometry of GPL nanofillers and porosity coefficient on the frequencies as well as flutter and divergence instabilities of the thin-walled porous beams have been studied. Numerical results demonstrate that the best efficient way to increase the stability region is considering GPL pattern A, with dispersing more GPL fillers near the top and bottom surfaces of the thin-walled porous beam along with symmetric porosity distribution.