Nonlinear Dynamic Analysis of Eccentrically Stiffened FGM Cylindrical Shells With Elastic Foundation Under Uniform External Pressure

The eccentrically stiffened cylindrical shells are one of the most important structures in aerospace industries. In this paper, semi-analytical method for eccentrically stiffened functionally graded (FG) cylindrical shells under external pressure and surrounded by an elastic medium is presented. The proposed model is based on Winkler and Pasternak elastic foundation parameters. According to the Von Karman nonlinear equations and the classical plate theory (CPT) of shells, strain displacement relations are obtained. The smeared stiffeners technique and Galerkin method, used for solving nonlinear dynamic problem. With considering three terms approximation for the deflection shape, the frequency-amplitude relation for non-linear vibrations obtained. The nonlinear dynamic response is obtained from fourth order Runge-Kutta method. The nonlinear dynamic buckling behavior of stiffened FGM shells is investigated based on the Budiansky-Roth criterion. The effect of parameters such as eccentrically stiffened, elastic foundation and excitation force on the frequency-amplitude curve of the nonlinear vibrations and parameters such as damping and loading speed on the nonlinear dynamic response of the FGM cylindrical shells have been investigated. The natural frequency, static and dynamic buckling load are analyzed, too.