The work is a further step towards optimization of stiffened cylindrical shells. Rings and stringers of non-uniform cross-section are analysed as a means of obtaining higher structural efficiencies. For lateral pressure loading, rings with non-uniform height or width are compared. The gain in general instability pressure relative to the uniformly stiffened shell of the same weight amounts to 70-80%. For prescribed loading, 10-20% weight savings are obtained. For axially compressed cylinders, stringers with sinusoidal and linear height variation are studied and compared. Gains in load and weight savings of 30% and 10%, respectively, are obtained, and the sinusoidal variation is found to be superior to the linear variation. Finally, cylinders under hydrostatic pressure stiffened by a combination of uniform stringers and non-uniform rings are analysed. Different configurations are checked in order to obtain the highest possible efficiencies. (Author)
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