AN INVESTIGATION OF THE PANEL COLLAPSE STRENGTH OF STIFFENED PLASTIC HEMISPHERES.
Technical rept. on Flight Sciences,
LOCKHEED MISSILES AND SPACE CO PALO ALTO CALIF RESEARCH LABS
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Sixteen 18-in. -diameter plastic hemispheres were tested to determine a method of analysis for predicting the collapse strength of panels between the ribs of a stiffened dome. Four hemispheres were unstiffened and 12 hemispheres were stiffened. Five of the 12 stiffened hemispheres had meridional and circumferential stiffeners. Three of the seven models had rib spacing assuming the panel between ribs buckled as shallow spherical segments. The other four domes had rib spacing assuming the panels buckled as flat plates. All of the hemispheres were tested to failure by subjecting them to an external crushing pressure. The results of this study show that panels between stiffeners of spherical shells can collapse at higher stresses than unstiffened shells, the collapse stress of panels between stiffeners can be predicted by an empirical equation, panels between stiffeners assumed to buckle as flat plates with simply supported edges is too conservative, panel bending stresses can be important for structures subjected to repeated loading conditions yet they may not influence the collapse strength, elastic buckling can occur for very shallow spherical panels, epoxy resin is a satisfactory material for experimental models, requiring high yield strength to density buckling characteristics. Author
- Containers and Packaging
- Submarine Engineering
- Structural Engineering and Building Technology