In the present study, the effects of reinforcement characteristics of a reinforced composite shell have been investigated on the buckling loads. Reinforcements with different cross sectionals but with the same area were arranged at equal intervals on the wall of the shell. For calculation of stiffness of the reinforced composite shell, the reaction between the shell and the reinforcements has been considered. In order to obtain the axial critical buckling load, Ritz method was used and obtained results compared with numerical simulations outputs. The boundary conditions of the shells are considered to be clamped or simple on both sides. Finally, the effects of geometry, kind, number and direction of the reinforcements were investigated. Also, variations of the buckling loads versus shell thickness and material, composition of composite layer and types of boundary conditions were studied. The results show that the thickness of the shell and I and T-shaped profiles for the reinforcements have the maximum effects on increasing the critical buckling load. It was also observed that with increasing the reinforcing angle, the critical buckling load of the shell decreases.
