Buckling Knockdown Factors of Composite Cylinders under Both Compression and Internal Pressure

The internal pressure of a thin-walled cylindrical structure under axial compression may improve the buckling stability by relieving loads and reducing initial imperfections. In this study, effect on knockdown factor is investigated for axially compressed composite cylinders with different shell thickness ratios slenderness ratios. Various are considered when derived both pressure. Nonlinear post-buckling analyses conducted using nonlinear finite element analysis program, ABAQUS. single perturbation load approach used to represent geometric imperfection cylinders. For cases compressive force only, decreases as ratio increases or increases. When simultaneously force, but factors considering compressions higher 2.67% 38.98% compared only. results show significant pressure, particularly thinner cylinders, that be enhanced all in study applied cylinder.