Influence of flatness on structural strength of end spherical bulkhead

摘要

The spherical bulkhead structure in style of sphere-toroid-cylinder combined shells is taken as the research object, and its structural strength with different "flatness" is studied. In order to characterize the geometric flat shape of the spherical bulkhead, the concept of "flatness" is put forward preliminary. Systematic numerical simulations of spherical bulkheads with different flatness are performed, and the effects of flatness on stress strength and ultimate bearing capacity are analyzed. The results show that stress on the inner-surface of the toroidal transition is significant with relatively small flatness, and the plastic deformation tends to soon occur and rapidly develop in the toroidal transition until the structure fails. And when the flatness is large (about larger than 0.7), there is high-level bending stress in the spherical shells and the ultimate bearing pressure is affected significantly by the initial deflection. The range of the flatness is suggested to be 0.35～0.55. The conclusion of this paper could provide a reference for the design of spherical-toroid-cylinder combined shells structure.