Static bending and free vibration analysis of multilayered composite cylindrical and spherical panels reinforced with graphene platelets by using isogeometric analysis method

This study makes an attempt at analyzing numerically the bending and free vibration behavior of multilayered composite cylindrical and spherical panels reinforced with graphene platelets (GPLs). A numerical model for the static and dynamic analyses of the GPL reinforced composite curved panels based on isogeometric analysis (IGA) combined with higher-order shear deformation shell theory is developed for the first time. NURBS (non-uniform rational B-spline) based IGA considered in the present investigation is capable of constructing exactly the complex geometries of the shell-type structures. The cylindrical and spherical panels are fabricated by stacking several layers in which the GPL concentration alters in a layerwise manner to form functionally graded (FG) structure. Uniform, FG-O, FG-X and FG-A types of GPL dispersions are taken into account. The Halpin-Tsai model is adopted to determine the effective modulus of elasticity, whilst the modified rule of mixture is utilized to estimate Poisson's ratio and the mass density of the nanocompoiste curved panels. The motion equations for the static and dynamic problems are derived from the higher-order shear deformation shell theory established based on the Reddy's shell theory, and NURBS based isogeometric formulation is made to obtain the central deflections and natural frequencies of the multilayered FG GPL strengthened composite curved panels. The validity of the present IGA method is first evidenced, followed by the illustrative parametric studies to further scrutinize the static and dynamic responses of the nanocomposite cylindrical and spherical panels with the various reinforcement schemes.