Experimental and theoretical correlations for elastic buckling of axially compressed stringer stiffened cylinders

Abstract

A re-examination of some 240 past experiments on the general elastic buckling of axially loaded stringer stiffened cylinders suggests that the observed buckling behaviours exhibited a degree of imperfection sensitivity considerably higher than that so often ascribed to them. It is demonstrated how the underestimation of these experimental knock-downs may have resulted from the use of theoretical models insufficiently representative of test conditions. By incorporating a more precise modelling of the test shells the present analyses show how, contrary to a widely held belief, the potential knock-down factors for general elastic buckling can approach those of the isotropic cylinder. Furthermore, despite the relatively perfect nature of many of the test shells, the recently described ‘reduced stiffness analysis’ method provides lower bounds of the observed experimental scatter that are sufficiently reliable to recommend this method as a basis for future design.