Effects of toroidal transition on strength and stability of submarine's cone-cone connection structure

  Objectives  The cone-toroid-cone structure is a new type of structure to solve the problem of stress concentration at the joint of two conical shells with different angles in a pressure hull of submarine. The pupose of this paper is to discuss the effects of the cone-cone shell transition on its connection structure, as well as the feasibility of the cone-toroid-cone structure and applicable range of conical angle.

  Methods  A series of ring-stittened cone-toroid-cone and cone-cone structural model are established using ANSYS finite element method. The typical stress and elastic stability of the two above mentioned transition sections at different cone angles are obtained using the models. Through comparative analysis, the influence of the toroidal transition on the mechanical properties of cone-cone structures with different angles is obtained.

  Results  The results show that the greater the difference in conical angle between the left and right conical shells, the greater the effect of reducing peak stress using toroidal shells. When the conical angle different on both sides (γ₁-γ₂ < 10°) is satisfied, the significance of using an toroidal shell transition is smaller. When the conical angle is small, the instability of the two structures occurs in conical shells with a smaller transition section radius, and the stability of the cone-toroid-cone structure is better than that of the cone-cone structure. Structural instability occurs in conical shells with a larger radius. The stability of the cone-toroid-cone structure is consistent with that of the cone-cone structure.

  Conclusions  The research results can provide references for the design and physical experiment of cone-cone connection structures.