Nonlinear buckling and post-buckling analysis of eccentrically stiffened functionally graded circular cylindrical shells under external pressure

The nonlinear buckling and post-buckling behavior of functionally graded stiffened thin circular cylindrical shells subjected to external pressure are investigated by the analytical approach in this paper. The shells are reinforced by eccentrically rings and stringers attached to the inside and material properties of shell and stiffeners are assumed to be continuously graded in the thickness direction. Fundamental relations, equilibrium equations are derived based on the smeared stiffeners technique and the classical shell theory with the geometrical nonlinearity in von Karman sense. Approximate three-terms solution of deflection is more correctly chosen and explicit expression to finding critical load and post-buckling pressure-deflection curves are given by using the Galerkinʹs method. The numerical results show the effectiveness of stiffeners in enhancing the stability of shells.