The Study On The Structural Performance Of Spherical Bulkhead For Submarine End

The end pressurized bulkhead is the important component of submarine pressurizedshell. It can be divided into flat bulkhead and spherical bulkhead according structural types.The flat bulkhead only used in special situation due to its structural characteristics.Spherical bulkhead are widely used in the single-shell and double-shell submarine pressurestructure with the advantages of light weight, space utilization.Usually, the spherical bulkhead of submarine end is consisted of three parts which areconical shell, transition toroidal shell and spherical shell. The spherical shell is subjected toalmost all the external pressure which is acted on the end pressurized bulkhead. The‘Methods for Design and Calculation of Submarine Structure’ which is used currently takesspherical shell as foundation to check the strength and stability of the end sphericalbulkhead and ignores the effects of conical shell and transition toroidal shell on the strengthand stability of the bulkhead. This paper presents the performance of the end sphericalbulkhead for submarine and the main contents are as follows:1. The formulas for design and calculation of pressurized spherical shells in the designrules which are used currently are introduced simply and the calculation results ofpressurized spherical shell’s work pressure according to different rules are compared withthe same structural parameter. The theoretical and empirical formulas of critical bucklingpressure for spherical shell are summarized and the buckling pressures of spherical shellcalculated with different formulas are compared under the same structural parameter.2. The relation of geometrical sizes for different parts is analysized when the endspherical bulkhead is semispherical shell and the calculation formula of the radius oftransition toroidal shell with different conical angle, conical length and radius of sphericalshell is obtained. The trends of different parts with conical angle are given out and thestability of spherical bulkhead is analysized with finite element software. The effects ofthree parts with changing parameters on the bulkhead are studied. The trends of thicknessesof three parts are obtained based on the uniform strength and are verified with finite elementmethod.3. The effects of the length of conical shell on the stability of spherical bulkhead iscalculated when the end bulkhead is spherical cap and the effects of other structural parameters are considered at the same time. At last, the stability formula of sphericalbulkhead in ‘Methods for Design and Calculation of Submarine Structure’ is modified andthe influence coefficient of conical length is put forward.4. The effects of different location of stiffeners on the critical bucking pressure arestudied and the theoretical foundation to decide the stiffeners locations is provided. Theeffects of different locations and different amplitudes of imperfections on the stability ofpressurized spherical shell are obtained. The different types of stiffeners are adopted for thepressurized spherical shell with initial imperfections and the buckling pressures of sphericalshell with different strengthened styles are compare and the optimized stiffeners styles aregiven out for the pressurized spherical shell with initial imperfections.