Research On Stability Of Sphere-cylinder Combined Shell Of Single Shell Submarine

The pressure hull structure of submarine is the primary key that related to the overall performance of the submarine and how to withstand the water pressure. With the development of the submarine technology, large depth, high speed and low detectable performance has become iconic index of modern submarine, and in recent years, some new type of submarine' size has a tendency to increase, all this need higher requirements about the strength and stability of the submarine pressure hull, So, studying the strength and stability of sphere-cylinder combined shell which is the major form of the pressure hull structure of submarine, have important theoretical and practical significance. Main work content is as follows:(1) Explore using the longitudinal reinforcing rib to improve the performance of stability of cylindrical shell. The stability formulas of the cylindrical shell with longitudinal reinforcing rib was deduced by energy method, compared with the formula of pressure cylindrical shells with circumferential reinforcing rib, to find out the influence law of various parameters on the stability of the stiffener. Discussing how to improve the stability of the cylindrical shell with longitudinal reinforcing rib and using the finite element method for validation.(2) According to the symmetry of spherical shells, ignoring the different of the instability of waveform, any slab beams that through the centre of sphere has the same deformation. The spherical shell can be simplified to a lath beam, to study the range of instability using the energy method, and considering the different influence of two reinforcing methods that the longitudinal reinforcing rib and circumferential reinforcing rib, two reinforcement ways of scope of spherical shell instability, finally summarizes the laws.(3) The stability formulas of the spherical shell was deduced by energy method, compared with empirical formulas to verify the reliability and practicability. And the stability formulas of the spherical shell with the longitudinal reinforcing rib and circumferential reinforcing rib was deduced, finding out the influence law of various parameters on the stability of the spherical shell with two different reinforcement methods, studying the application of reinforcement to improve the stability of the spherical shell.(4) Compared the formulas of spherical shell and cylindrical shells, finding the conditions of different buckling modes. When occur the overall instability of sphere-cylinder combined shell, on the basis of end boundary conditions and continuity conditions of composite shell, set the displacement function and deriving the overall stability formula of sphere-cylinder combined shell. Using numerical method to simplify the formula and To verify this formula with the finite element method, and deriving the stability formula of another two local buckling.