Buckling behaviour of double-layer and single-layer stainless steel cylinders under external pressure

This study focused on the buckling behaviour of double-layer (DL) and single-layer (SL) stainless steel cylinders under uniform external pressure. Such cylinders are short thin-walled cylindrical shells of revolution. Three nominally identical DL cylinders and three nominally identical SL cylinders were designed, fabricated, geometrically measured, and subjected to hydrostatic testing. The length-to-diameter ratio of all cylinders was 1.7, while the thickness-to-diameter ratio was 0.0125 for SL cylinders and 0.0261 for DL cylinders. Analytical and numerical approaches were used to evaluate the buckling behaviour of experimental cylinders. Furthermore, the effects of initial clearance and imperfection on the ultimate strength of DL cylinders were studied. The results revealed that DL cylinders are clearance-sensitive and imperfection-sensitive structures. The imperfectionsensitivity of DL cylinders were determined by sublayered cylinders because they had nearly the same imperfection-sensitivity. The average ultimate strength of DL cylinders was approximately 1.62-times higher than that of SL cylinders. The clearance sensitivity and imperfection sensitivity decreased with the increase of length-to-thickness ratio.