The influence of uncertainties on the buckling response of thin curved composite panels with multiple cutouts

This study presents an analytical approach for buckling load predictions as the second level of a "High-Fidelity Hierarchical Analysis." Of particular concern is the investigation of the influence of thickness variation, non-uniform end shortening (load introduction), and the stiffness of the clamped-edge support fixture (boundary condition) on the buckling strength of the thin-walled cylindrical composite panels with multiple cutouts. This approach is based on the principle of minimum potential energy, utilizing local and global functions. The local functions capture the steep stress gradients and local deformations around the cutouts. The kinematic boundary conditions are imposed by employing linear and torsional springs. The analysis involves two consecutive steps: (1) a pre-buckling state providing the membrane stress distribution prior to buckling and (2) the buckling state caused by membrane stresses proportional to the reference (pre-buckling) state. For a panel with a single hole, the influence of variable thickness, the elastic edge restraints, and the non-uniform end-shortening of the cylindrical panel due to eccentric loading on the buckling response of the panel are investigated. This analysis provides credible estimates of the buckling loads.