This paper focuses on the elastic buckling of cross-ply composite closed cylindrical shell subjected to hydrostatic pressure. The analytical model for buckling of composite cylindrical shell is derived by using the First Order Shear Deformation Theory (FOSDT) and considering the pressure stiffness. Several types of shells including thin, thick, long, and short shells are investigated. Two composite materials i.e. Carbon/Epoxy and Glass/Epoxy and several layup configurations are employed. The results of the derived FOSDT-based model are compared with those obtained from a Shell Buckling Equation (SBE) used in earlier studies and the Classical Shell Theory (CST). For verification, the results of the derived FOSDT-based model are compared with the results found in literature and also with the results obtained from finite element analysis. The difference among the results of the SBE and FOSDT, and the CST and FOSDT increases with the increase of the thickness in the case of all layup configurations and materials. For thin shells, the difference between the results of the CST and FOSDT almost vanishes, while for thin and large shells, the difference between the results of the SBE and FOSDT is still significant.

本文重点研究了承受静水压力的正交复合材料闭合圆柱壳的弹性屈曲。利用一阶剪切变形理论（FOSDT）并考虑压力刚度，推导了复合材料圆柱壳屈曲的解析模型。研究了几种类型的壳，包括薄壳，厚壳，长壳和短壳。使用两种复合材料，即碳/环氧树脂和玻璃/环氧树脂以及几种铺层构造。将导出的基于FOSDT的模型的结果与从早期研究中使用的壳屈曲方程（SBE）和经典壳理论（CST）获得的结果进行比较。为了进行验证，将导出的基于FOSDT的模型的结果与文献中的结果以及从有限元分析中获得的结果进行比较。在所有叠层配置和材料的情况下，SBE和FOSDT以及CST和FOSDT的结果之间的差异会随着厚度的增加而增加。对于薄壳，CST和FOSDT的结果之间的差异几乎消失，而对于薄壳和大壳，SBE和FOSDT的结果之间的差异仍然很大。