Method for estimating ultimate bearing capacity of pressure-resistant spherical shell of high-strength steel submersible

Abstract

The invention discloses a method for estimating ultimate bearing capacity of a pressure-resistant spherical shell of a high-strength steel submersible. The method comprises the steps of 1: setting spherical shell related parameters including the mean diameter r of the spherical shell, different thickness values t and different yield strength sigma y; 2: researching the influence of the yield strength of a material on the bearing capacity of the spherical shell; defining the influence of the yield strength on the ultimate bearing capacity of the spherical shell as a plastic attenuation factor kp and performing solving; 3: obtaining a perfect nonlinear critical buckling load Pnon:pnon=kppm t of the spherical shell; 4: researching a law of influence of geometric initial defects on the buckling load of the spherical shell, and defining the influence of the geometric initial defects on the ultimate bearing capacity of the spherical shell as a geometric defect attenuation factor kimp and performing solving; 5: concluding an estimation formula for the ultimate bearing capacity Preal of the spherical shell: preal=kpkimppm t; and 6: according to related parameter values of an actual shell, searching for corresponding data, substituting the data into related formulae, and finally working out the required ultimate bearing capacity Preal of the spherical shell.

Description

technical field [0001] The invention relates to a method for estimating the ultimate bearing capacity of a pressure-resistant spherical shell of a high-strength steel submersible. Background technique [0002] As an important part and buoyancy unit of the submersible, the pressure hull plays a role in ensuring the normal operation of internal equipment and the health and safety of personnel during the diving process. Its weight accounts for 1 / 4-1 / 2 of the total weight of the submersible. Most of the existing pressure hulls are spherical structures, and the accurate prediction of their ultimate bearing capacity has an important impact on the safety and economic performance of submersibles. [0003] The Code for Classification and Construction of Diving Systems and Submersibles (CCS2013) provides a prediction method for the ultimate bearing capacity of the relevant spherical shell. First, the numerical calculation prediction method, through the simulation calculation of the f...

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Problems solved by technology

[0007] After years of research and summarization, finite element numerical calculations can predict the bearing capacity of spherical shells more accurately, but various model parameters need to be set during software calculations, and parameter deviations have a great impact on the results; and there is a lack of systematic research on the mechanism of shell instability and identification

At the same time, the calculation formula provided by the classification society can only predict the bearing capacity of the titanium alloy spherical shell under specific circumstances, while high-strength steel has been widely used in pressure shells, this calculation formula is not suitable for materials such as high-strength steel

And the formula only involves the tensile strength of the material, without considering the instability mechanism of the pressure-resistant structure, and the formula does not involve the relevant parameters of the material, such as yield strength E, elastic modulus μ and yield strength σ y , while the buckling behavior of spherical shells is often closely related to the yield strength

[0008] Therefore, the prediction method of the ultimate bearing capacity of the spherical shell lacks a more systematic and widely used prediction method suitable for high-strength steel

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