Buckling analysis of composite lattice cylinder whit inner and outer shell under external pressure

In recently years, Stiffened cylindrical shells are used in the major components of aviation, missile and marine structures. In this study has been analyzed buckling of composite lattice cylinder with inner and outer shell under external pressure. This was accomplished by developing an analytical model for determination of the equivalent stiffness parameters of a grid stiffened composite cylindrical shell. This stiffness contribution of the stiffeners was superimposed with the stiffness contribution of the shell to obtain the equivalent stiffness parameters of the whole panel. Equations governing the cylindrical lattice structures are solved based on the displacement and stress-strain relations in the form of a matrix using classical shell theory under boundary conditions clamp supported and simply supported. The results show increase in grid cell length, angle and cross-section parameters caused increase in stiffness and critical buckling load but increase further them cause local and global buckling. Finally for all of them can be considered optimal value and for prevent local and global buckling and the effectiveness of the lattice structure to a limited number of stiffener with optimal angle, longitudinal and cross sections required.