Compression buckling of elastically supported cylindrical shells with Bend/Twist coupling

Composite cylindrical shells are widely used in space launch systems due to their high load-carrying capability and for being lightweight. However, these structures are prone to buckling phenomena at much lower loads than classical predictions for perfect cylinders. This work aims to develop data-driven empirical expressions to calculate the upper and lower bound values of cylindrical shells under linear compression loads with various boundary conditions together with various levels of bend/twist anisotropy. The inclusion of bend/twist coupling effects is a major development. To do so, the critical buckling load for laminated thin-walled cylindrical shells on elastic foundations with low, medium and high levels of bend/twist anisotropy were investigated. Then, an analysis-driven design approach is proposed to estimate the upper and lower bounds of buckling loads for axial, radial and tangential elastic foundations. Subsequently, parametric studies were performed with various combinations of bend/twist anisotropy and laminate thicknesses using Abaqus finite element models, and a comparison was made with the proposed data-driven empirical buckling load expressions. Finally, results show that the detrimental effect of boundary conditions and inherent bend/twist anisotropy could lead to a 61% reduction in buckling load, providing a need for detailed studies in this area.