Nonlinear Bending Analysis of Composite Cylindrical Shells Reinforced by Functionally Graded Carbon Nanotube in Circumferential Direction

In this study, nonlinear axisymmetric bending analysis of Functionally Graded Carbon Nanotube Reinforced Composite (FG-CNTRC) cylindrical shell is investigated. Four distribution types of carbon nanotubes along the thickness direction of shells are considered, including a uniform and three kinds of functionally graded distributions. The material properties of FG-CNTRC shells are determined according to the modified rule of mixture. The equilibrium equations are derived based on First-order Shear Deformation Shell Theory (FSDT) and nonlinear Donnell strains. The coupled nonlinear governing equations are solved by Dynamic Relaxation (DR) method combined with central finite difference technique for different combinations of simply supported and clamped boundary conditions. For this purpose, a FORTRAN computer program is provided to generate the numerical results. In order to verify the accuracy of the formulation and present method, the results are compared with those available in the literatures for ABAQUS finite element package, as well as a similar report for an isotropic function shell. The appropriate accordance of the results indicated the accuracy of employed numerical solution in the present study. Finally, a parametric study is carried out to study the effects of distribution of carbon nanotubes (CNTs), shell radius and width-to-thickness ratios, boundary conditions and volume fraction of CNTs on the deflection, stress and moment resultants in detail. The results show that with increase of CNTS volume fractions, the O and UD distributions have the most and the least decrease of deflection, respectively, in both clamped and simply supported boundary conditions.