Large deflection analysis of FG-CNT reinforced composite pipes under thermal-mechanical coupling loading

Abstract

This study is concerned with the analysis of large deflection in composite pipes reinforced with carbon nanotubes (CNTs) resting on nonlinear elastic foundation. It is assumed that the nanocomposite pipe is subjected to uniformly distributed transverse pressure loading and also uniform temperature rise. Distribution of CNTs is functionally graded (FG) through the radius of composite pipe and material properties are assumed as temperature-dependent. Two kinds of immovable boundary conditions are considered for the composite pipe which are simply-supported and clamped. The principle of virtual displacement is employed to establish the nonlinear equilibrium equations of the composite pipe under thermo-mechanical loading. Governing equations are extracted based on the higher-order shear deformation theory and the von Kármán geometric measure. The system of nonlinear differential equations is analytically solved utilizing the two-step perturbation technique and Galerkin method. Results of this paper are compared with the available data in the literature for the homogeneous isotropic pipes. The effects of boundary conditions, geometric factors, CNTs distribution profile, foundation stiffness, and the volume fraction coefficient on the bending behavior of FG-CNT reinforced composite pipes are discussed in detail. The novel results of this study demonstrate that the maximum deflection of the nanocomposite pipe occurs in the FG-Λ pattern and the minimum deflection belongs to the FG-V case.