Effect of opening and boundary conditions on compressive buckling properties of composite one-third cylindrical shell

The compressive buckling properties of three types of composite one-third cylindrical shells were studied, including intact shell, shell with reinforcement around the opening hole and shell with opening hole and cover. The effect of opening and cover on compressive stability of cylindrical shell was analyzed through the axial compressive buckling strength of three typical composite cylindrical shells. The results show that the opening hole significantly decreases the axial compressive buckling strength. Although axial compressive buckling strength can be restored partly by applying a cover, it can hardly be restored as it was. Axial compressive tests of warp knitting fabric composite one-third cylindrical shells with opening hole and cover were conducted. Compared with the identical structures made of flat knitting composites, the axial compressive buckling strength decreases obviously. In order to explore the cause for the serious axial compressive buckling strength drop, finite element analysis of composite one-third cylindrical shell model with nonuniform loading was conducted. The numerical results show that nonuniform boundary loading decreases the bearing capability and designing the boundary loading according to shell stiffness distribution can improve the bearing capability.