环向肋增稳的薄壁圆筒结构定向拓扑优化方法

针对广泛应用于飞行器的薄壁圆筒结构，在优化设计时未考虑薄壁特性导致优化结果加工性和稳定性欠佳的问题，提出一种面向飞行器总体设计阶段的环向肋增稳薄壁圆筒结构定向拓扑优化方法。该方法首先依据薄壁结构壁厚方向将有限单元划分成组，以单元组为基本单位构成优化设计空间，保证优化结果具有定向性，进而保证优化结果符合薄壁结构加工特性；然后引入环向加肋稳定性增强策略，通过设计空间修正方法在有限元模型中等效添加环向肋，对结构进行稳定性增强。将该方法应用到火箭级间段结构优化中，优化后方案能够同时兼顾加工性和稳定性，相比于原始方案的屈曲系数提升32.21%，结构减重19.05%。结果表明，该方法充分考虑了结构的薄壁特征，优化后的结构具有较好的加工性和稳定性。

Oriented Topology Optimization of Thin walled Structure with Circumferential Rib Enhancement of Stability

In order to solve the problem that the thin walled characteristics are ignored during the process of topology optimization of thin walled cylinder structure in the overall design stage of rocket liked vehicle, which results in the poor processability and stability of the optimized result, an oriented topology optimization method of thin walled cylinder structure considering the stability performance is proposed. Firstly, the finite elements are divided into groups according to the machining direction of thin walled structures, and the optimization design space is recomposed of the basic unit of the elements’ group, which ensures the orientation of the optimization results and conforms to the machining characteristics of thin walled structures. Then, the stability compensated strategy of adding circumferential ribs is introduced to the flow of optimization, and the circumferential ribs are added to the finite element model by modifying the design space, ensuring the optimized structure has better performance of stability. The proposed method has been applied to the structural optimization of rocket interstage, and the simulation results show that the proposed method has good processability and can maintain the stability of the structure under the design load. Compared with the original scheme, the buckling coefficient is increased by 32.21% and the weight of the structure is reduced by 19.05%. The results show that the thin walled characteristics of thin walled structure are fully considered by this method, and the optimized structure has good processability and stability.