Expressions of Load and Structural Deformation Relationship for Cylindrical and Spherical Vessels Under Internal Pressure

Large deformation analysis for pressure vessel is much more complex than small deformation analysis, therefore, right now, there is no common recognized direct solution for load bearing capacity of pressure vessel yet, and this restrict the application of large deformation analysis in pressure vessel design. This paper based on elastic-plastic theory and considered material strain hardening and structural deformation effects, expressions of load and structural deformation relationship were the first time being derived for cylindrical and spherical vessels under internal pressure. And its practical value is equivalent to principal stress equations of thin-walled cylindrical and spherical vessels with considering non-linear structural deformation effect. Based on the study above and by introducing true stress-strain relationship of materials, analytical solutions of plastic instability pressure for thin-walled cylindrical and spherical vessels were derived.