The method of tangent modulus factor for the design of external pressure vessels

To solve the problems such as too much trial-and-error, limited material being involved in the graphs and calculation results being obviously influenced by artificial factors and errors of the graphs in the design of external pressure vessel according to current standard ASME VIII-1, GB150 and EN13445, the mathematic expression of the graphic charts is examined, and a set of analytical equations and algorithms for the linear and nonlinear instability of external pressure vessel are established. The equation was applied to calculate the ultimate buckling pressure of cylinder and spherical shells. The algorithm here provided can not only avoid the shortages of current graphic analysis methods, but also be convenient for technicians to calculate, which could enrich and consummate the graphic charts in the current standards and be useful to the design of external pressure vessels to be made of new materials.