Optimization Of Structure Design To Strengthen The Underwater Sealing Cover

Spherical shell is a common structure form in areas such as scuba diving equipment, aerospace, pressure vessels, and nuclear industry. Spherical shell buckling in a very common phenomenon, So studying the damage mechanism and reinforcement of spherical shell has very important significance.This paper is based on organic glass sealed spherical shell as the research object, and nonlinear finite element methods, analyzing the failing mechanism of organic glass spherical shell under outer pressure loading, and calculating the critical load pressure. The result shows that the spherical shell occurs buckling under external pressure load, and then the confined ability drops. When the displacement reaches a certain value, the stability problem will turn into intensity problem, and the value of the first principle stress of spherical shell reaches the tensile strength of the organic glass, and the brittle fracture of spherical shell occurs. When strengthening spherical shell with different thickness of bodies 137mm-400mm below the spherical shell, and the results of linear analysis calculation shows that, when strengthening the body at the bottom of the eight-sided ring, laying with the increase of the thickness of the bodies, the value of critical pressure also increase. Compared to non-strengthening spherical shell, the critical pressure only increases by 2.5% when the thickness is 6mm. The results show that the area below spherical shell is not sensitive to strengthen, strengthening body in the below area can hardly increase the ability of under pressure of spherical shells.While strengthening over the region of spherical shell, some area is sensitive to strengthen. In the region of 440mm to 518mm highly equipped to strengthen body, the critical pressure curve is very flat, and it’s not obvious of the effect of strengthening the body. In the region of 528mm to 536mm highly strengthening the body, the critical pressure curve is very steep, the strength effect is most obvious, and it shows that this part is sensitive to strengthen, so it is preferred to strengthen the body in this height range and its adjacent area. Design three kinds of spherical shell models with different thickness bodies, to improve critical pressure value of the spherical shell by more than 20%, and verify the safety of the spherical shell by analyzing the inner pressure of designed spherical shell.It has reference significance of the research methods and results in this paper, for the stability design and optimization of fragile shells structure.