A Parametric Study of Elastic-Plastic-Creep Buckling of a Thin Cylindrical Shell

The elastic-plastic-creep buckling of a long thin cylindrical shell with initial out-of-roundness subjected to uniform external pressure is herein studied. The work is carried out by means of an economical computer program which consistently accounts for the effects of load changes and plastic strains and which has a calculation procedure based on direct integration. The ratio of the sustained load to the initial buckling load is discovered to be a parameter which relates the sustained load to the buckling time without explicit reference to the geometric parameters for the conditions considered. Other results are uncovered concerning the effect of: the shape of the imperfection, the temperature variations and the choice of creep relations on initial buckling load and buckling time. Alternatives to the expensive and time consuming calculations to meet the requirements of the time factor of safety on Code Case 1331 of the ASME Boiler and Pressure Vessel Code for Class 1 nuclear components are explored. Recommendations are made.