Lightweight design of a clamp band joint via a constrained sequential approximate optimization method in the irregular design domain

The clamp band joint (CBJ) is a multi-component and complex device for connecting and separating satellites from launch vehicles. In this article, the pre-tightening and connection process are analysed sequentially through an implicit–explicit calculation method. Because of the time-consuming nonlinear analysis, a constrained sequential approximate optimization (CSAO) method in the irregular design domain is proposed for the lightweight optimization design of CBJs. A novel constrained space-filling and non-collapsing sequential sampling method is adopted to address the sampling inefficiency of conventional experimental designs in the irregular domain, while the sequential sampling of exploration and exploitation strategies is balanced for the global and local approximation accuracy. Finally, comparison with the traditional sequential approximate optimization method shows that the proposed method can search the optimum in the feasible region more efficiently. Besides, compared to the initial design, the optimized structure improved the connection stiffness by 56.7% and reduced the weight by 8.3%.箍带连接机构（clamp band joint, CBJ）是一种用于卫星与运载火箭连接与分离的多组分复杂装置。本文采用隐式-显式计算方法（implicit–explicit calculation method），依次对预紧与连接过程展开分析。鉴于非线性分析耗时较长，针对箍带连接机构的轻量化优化设计，本文提出了一种不规则设计域下的约束序列近似优化（constrained sequential approximate optimization, CSAO）方法。为解决常规试验设计（experimental design）在不规则域内采样效率低下的问题，本文采用了一种新型约束空间填充无折叠序贯采样方法（constrained space-filling and non-collapsing sequential sampling method），通过平衡探索与利用策略（exploration and exploitation strategies）的序贯采样，兼顾全局与局部近似精度。最后，通过与传统序列近似优化方法的对比验证，本文所提方法可在可行域内更高效地寻得最优解。此外，相较于初始设计，优化后的结构连接刚度提升了56.7%，重量降低了8.3%。