Vibration analysis of fiber reinforced composite sandwich cylindrical shells with FG-GPLRPC core under discontinuous boundary conditions

In this study, the free vibration characteristics of sandwich cylindrical shells under discontinuous elastic boundary conditions are analyzed. The face layers of the shell are composed of fiber reinforced composite (FRC) material, while the core layer consists of functionally graded graphene reinforced porous composite (FGGPLRPC) material. The equivalent material properties of FG-GPLRPC are determined by the Halpin-Tsai micromechanical model. By employing the first order shear deformation theory and the continuity assumption of the layerwise theory, the Energy expressions of the sandwich shell are obtained. Furthermore, the artificial spring technique is used to simulate the discontinuous boundary. Based on the state space method, and RayleighRitz method, the natural frequencies of the shell are calculated. Comparison of the calculated results with those in the literature confirms the model's reliability in predicting relevant dynamic parameters. The effects of several parameters on intrinsic frequency are examined, such as the mass fraction of graphene, the ply angle of the fibers, and the radian range of arcs-supported areas under various discontinuous elastic boundary conditions.