PHOTOELASTIC INVESTIGATION OF STRESS CONCENTRATIONS IN SPHERE-CYLINDER TRANSITION REGIONS: INCLUDING A COMPARISON OF RESULTS FROM PHOTOELASTIC AND FINITE ELEMENT ANALYSES.
Final rept. 1 Jul 66-30 Jun 67,
NAVAL CIVIL ENGINEERING LAB PORT HUENEME CALIF
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The study investigates stress distributions in sphere-cylinder transition regions of externally pressurized thick-walled vessels it compares data determined by two different approaches photoelastic analysis and finite element computer programs. These approaches afford a capability for analyzing complicated deep ocean structures that are of considerable interest to the U. S. Navy. Two small-scale epoxy models of the prototype structures were loaded by 4- and 10-psi external pressure at a critical temperature 290F and then the stresses were frozen by cooling the material. The first model had relatively thin walls cylinder diameter-to-wall thickness ratio 15, and incorporated 60 balanced opening reinforcement at the transition. The amount of reinforcement is expressed as a percentage of the material removed from the vessel shell to form the opening. The reinforcement is balanced when equal amounts are placed on the inside and outside of the vessel. The second had a cylinder diameter-to-wall thickness ratio of 4, and 65 balanced opening reinforcement. After stress freezing, the models were sliced longitudinally and transversely and the meridional and circumferential stresses were determined photoelastically with a diffused-light polariscope. The photoelastic solutions were used to verify the stresses calculated by finite element computer programs. Excellent correlation was obtained for the comparison of meridional and circumferential surface stresses by the photoelastic and finite element procedures. AUTHOR
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