The Effect of Floating Rings on the Stability of Longitudinally Stiffened Cylinders in Axial Compression

Citation

Sullivan, Timothy Lay (1961) The Effect of Floating Rings on the Stability of Longitudinally Stiffened Cylinders in Axial Compression. Engineer's thesis, California Institute of Technology. doi:10.7907/3MBR-S755. https://resolver.caltech.edu/CaltechETD:etd-12212005-135322

Abstract

An experimental investigation was conducted to determine the effect of floating rings on the stability of longitudinally stiffened, thin-walled cylinders in axial compression. Mylar and Plexiglas were used as the skin and stiffening materials, respectively. The primary objectives of the investigation were: (1) to determine the increase in buckling stress that could be obtained by the addition of floating rings; (2) to determine the ring stiffness required for the maximum cylinder strength; (3) to determine what effect the number of longitudinal stiffeners had on the ability of the rings to increase the buckling stress; and (4) to examine the mechanism of buckling in the various ring-stringer combinations. A strength-weight analysis was also made. The addition of rings was found to be very effective in increasing the cylinder buckling load when 24 longitudinal stiffeners were used. The addition of three rings to a cylinder with 24 longitudinal stiffeners increased the buckling load 123 per cent with only a 20 per cent increase in weight. The ring stiffness beyond which there was no more increase in cylinder buckling strength was determined for the 24 stringer, two and three ring configurations. The ability of a ring to increase the buckling stress was markedly decreased when the number of longitudinal stiffeners was decreased from 24 to 12. The mechanism of buckling was also affected by the number of rings and longitudinal stiffeners. In the light of the experimental results, two analytical methods are suggested for predicting the buckling stress of floating ring stiffened cylinders.

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