A Simplified Method for Calculating Ultimate Strength of Pressure Hull in Deep-Sea Manned Submersible

Abstract

Based on the strain energy density theory, the connotation of tangent modulus theory is developed. At critical equilibrium state, a dimensionless number Φt of a structure under pressure is introduced in this paper. Derived from the stress-strain curve of material, a four-parameter formula that contains Φt is established. This formula is referred to as the function of strength utilization ratio that may be used for calculating the inelastic buckling of deep submersible pressure hull.Φt can be used to express the effect of initial imperfection of the shell and to guide the experimental study. Compared with the data from some experiments or other methods, it has demonstrated that the method given by this paper is more precise and convenient for predicting the failure of thin and moderately thick shell under pressure.