球-环-柱型式球面舱壁静强度及承载能力分析

Study of static strength and load-bearing capacity of spherical-toroid-cylinder spherical bulkhead

以球-环-柱组合壳型式的球面舱壁结构为研究对象,分析不同几何形状下球面舱壁结构静强度及承载能力的特性。为表征球面舱壁扁平几何形状,初步提出"扁平度"的概念,借助结构有限元软件,对系列不同扁平度球面舱壁模型进行计算,分析其对结构静强度及极限承载能力的影响作用。研究表明:当球面舱壁扁平度较小(约小于0.2)时,过渡环段的内表面应力强度问题突出,容易产生塑性变形并扩展至整个过渡环段,并在过渡环区域发生破坏;当扁平度较大(约大于0.7)时,球壳区域出现弯曲应力,初挠度影响较为敏感,易在初挠度区域产生塑性变形导致结构失效;建议扁平度取值范围为0.35~0.55,对应球面舱壁极限承载能力相对较高。本文的研究结论可为球-环-柱结构设计提供参考。

A spherical bulkhead structure in style of sphere-toroid-cylinder combined shells is taken as the research object, and its structural strength characteristic 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 when the flatness of the spherical bulkhead is small（about less than 0.2）, the stress on the inner-surface of the toroidal transition is great, 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.