Minimum-Weight Design of Stiffened Cylindrical Panels under Combined Loads

Theme T HE increasing demand for lightweight structures has made the structural engineer more conscious of minimum-weight design. Since stiffened cylindrical shells have been used extensively during the past thirty years in underwater, surface, and aerospace vehicles, a tremendous effort has been exerted in designing such a configuration for minimum weight. A methodology was developed and demonstrated by the first author and his collaborators" for designing a stiffened cylinder, subjected to various load conditions with minimum weight when at least one of the active modes of failure is known a priori. The nonmenclature employed herein is identical to that of Refs. 1-4. Since the structural geometry of the above-mentioned vehicles (aircraft fuselage, submarine hull, etc.) is best represented by a combination of stiffened cylindrical panels, the methodology is, herein, applied to panels and extended to accommodate the combined application of loads. The precise statement of the problem considered, in this extension, is as follows: Given a stiffened thin cylindrical panel of specified material, radius of curvature, length and width, find the realistic size, shape, and spacing of the stiffeners, and the realistic thickness of the skin, such that the resulting configuration can safely carry a given set of surface loads with minimum weight.