Carrying Capacity of Pressure Vessels under Hydrostatic Pressure

To use material effective and keep pressure vessel safety, large de- formation analysis for pressure vessel is very important. Until 2007, the elastic- plastic stress analysis method, that is the first time all over the world, is provided in ASME VIII-2 edition 2007 for boiler and pressure vessel standard that Finite Element Method is used with large deformation analysis. But there is no com- mon recognized direct solution for the carrying capacity of pressure vessels yet and this restrict the application of large deformation analysis in pressure vessel design. This paper investigates the carrying capacity of pressure vessels under hydrostatic pressure, based on the elastic-plastic theory. Firstly, to understand the large defor- mation characteristic of pressure vessel, the expressions of pressure and strain of thin-walled cylindrical and spherical vessels under internal pressure is reviewed. Secondly, to investigate the solution of carrying capacity of pressure vessels, the plastic instability criterion is derived. Further, the method to obtain the carrying capacity of pressure vessels is given for all pressure vessel material and two repre- sentative examples for analysis solutions of cylindrical and spherical pressure ves- sel respectively are given. The proposed research can be used for the elastic-plastic stress analysis method of pressure vessels safely.