潜艇外部耐压液舱结构型式研究

  目的  为了简化建造工艺和减轻液舱结构重量，对外置式耐压液舱实肋板结构进行拓扑优化和开孔尺寸优化设计。  方法  首先，利用Hyperworks/Optistruct对外置式耐压液舱整体模型进行结构应力分析。然后，在拓扑优化中，除与液舱壳板和耐压船体壳板相连的约100 mm长条状范围外，以实肋板其他范围内的单元密度为设计变量；以与实肋板相连的液舱壳板和船体壳板上结构的典型应力及实肋板体积分数为约束，以实肋板上最大Mises应力最小化为目标，针对满载和空舱两种工况，利用商用软件Hyperworks/Optistruct对实肋板结构进行拓扑优化。最后，基于Matlab和ANSYS联合优化，以实肋板上von Mises应力和剪应力为约束，以相应结构重量极小化为目标，对实肋板开孔进行尺寸优化，从而得到精细化开孔方案。
  结果  拓扑优化结果表明，外置式耐压液舱实肋板开减轻孔应集中在中、下部。开孔尺寸优化结果表明，相比初始方案，实肋板剪应力增加38%，其他关注区域应力相当时，内部实肋板上结构重量可降低19%。  结论  两类优化设计均表明，外置式耐压液舱实肋板开减轻孔应集中在中下部，且从下到上开孔面积应逐渐减小。

Research on the structural forms of outer pressure tank of submarine

  Objectives  In order to simplify the construction process and to reduce the weight of the structure, topology optimization and opening size optimization of solid floors in an outer tank of the pressure hull are conducted.  Methods  In the study, Hyperworks/Optistruct is adopted to analyze the strength characteristic of the whole structure. The part of the solid floors 100 mm away from outer tank and pressure hull is defined as design space of the topology optimization. And the elements densities within the defined design space are taken as the design variables. The volume fraction of the design space and the typical stress values of the pressure hull and outer tank are assumed as design constraints while the objective is to minimize the maximum stress on the solid floors. Hyperworks/Optistruct is used to optimize the solid floor in outer pressure tank under full and empty loadings.
Then, the size optimization of opening based on the Matlab and ANSYS is conducted. The von Mises and shear stresses of the solid floor are regarded as design constraints, and the weight of the solid floor including the stiffeners on them is treated as objective function to be minimized. A precise optimal scheme of openings is obtained through the above process.  Results  The result of topology optimizations shows that holes should be placed on the middle to lower part of the solid floors. The result of opening size optimizations indicates that, compared with the initial scheme, the weight of the optimal solid floor with opening is decreased by 19% with the 38% increase in shear stress and equivalent levels of the other stresses.  Conclusions  Both the optimization designs show that openings should be placed on the middle to lower part of the solid floor and their size should be gradually decreased from lower part to middle part of the solid floor.