Experimental and numerical investigation of CFRP cylinders with circular cutouts under axial compression

Thin-walled cylindrical structures are widely used in aerospace, offshore, civil and other engineering fields. Parts of space launcher transport systems are one example for the application of such shells. Buckling of thin-walled structures is a very important phenomenon to be considered during their design phase. This is true not just because such structures are often imperfection sensitive (geometry, boundary conditions, load introduction, thickness, etc.) but also due to operational requirements set on these thin-walled structures which often lead to the need for introducing cutouts to accommodate access panels, doors and windows. These cutouts constitute an additional factor that influences the overall stability and needs to be understood in order to enable a safe operation and an effective design of these structures. The study deals with buckling experiments on two axially compressed, unstiffened CFRP cylindrical shells with circular unreinforced cutouts, performed by DLR. Moreover, a FE model is described that is validated with the experimental results. The objective of the study is to investigate the effect of the size of the cutouts on the buckling characteristics of the tested shells.