Experimental investigation of the strength of short thin-walled cylinders, subjected to radial internal pressure

Abstract

1. Laws have been found relating breakdown pressure with wall-thickness for short cylinders and normal and elevated temperature and also for loading over part of the length. The breakdown pressure of short cylinders, in the form of high-strength containers of steel, possessing some plasticity margin, can be calculated, for a loading length hH/h=0.50–0.75 from the membrane stress formula for the cylinder inside diameter. 2. Tests of thin-walled cylinders at elevated temperature showed different behavior for type 5 and type 27 steels. Because of increased plasticity cylinders of type 5 steel, after breakdown at the temperature of 450°C, had a greater barrel factor (7–12%), in comparison with cylinders of type 27 (1.5–8%), while the breakdown pressure for the type 5 and type 27 steels were decreased by 27 and 16%, respectively, compared to the breakdown pressures at room temperature. 3. The effect of test temperature on the nature of thin-walled cylinders was studied. At room temperature cylinders loaded over part of the length broke down by rupture along a straight generator, while cylinders of the coarser type 27 steel broke up into several parts. At elevated temperature breakdown begins due to rupture in the maximum deformation zone, and then propagates towards the ends through shear, at an angle relative to the cylinder axis. As a rule, both at normal and elevated temperature, breakdown begins at the outer surface in the maximum deformation region. 4. New methods have been developed and verified experimentally for testing short thin-walled cylinders subjected to internal pressure at normal and elevated temperature; the methods involve the use of compression and allow investigations of breadkown pressure for different loading lengths.