Experimental and numerical investigation of buckling behavior of composite cylinders with cutout

This manuscript employed experimental and numerical procedures to investigate the effects of initial geometric imperfection on the buckling behavior of the perfect and perforated composite cylinders. In the numerical part, linear eigenvalue analysis of the perfect cylinder showed a large discrepancy in comparison to the NASA SP-8007 guideline from 1968. However, results were considerably enhanced by performing a nonlinear analysis where initial geometric imperfection was simulated using Single Perturbation Load Imperfections (SPLI) and Linear Buckling Mode-shaped Imperfections (LBMI) techniques. Numerical analyses were performed for three different groups of the perforated cylinders to evaluate the effect of the growing cutout size on the buckling behavior. In addition, the mutual effect of the cutout and the initial geometric imperfection on the buckling analysis were investigated. Results confirmed that cutout effect is dominant, for the cylinder under consideration, so considering initial geometric imperfection has a negligible effect on the predicted buckling load. In the experimental part, perfect and perforated glass/epoxy composite cylinders with a stacking sequence of [90/+23/−23/90] were manufactured using filament winding technique and tested under compressive axial loading. Buckling test data of the perfect and perforated cylinders showed an acceptable correlation with the numerical results obtained using the nonlinear analyses methods.