Optimal design of shell-lattice infill integrated supporting structure based on Moving Morphable Components method and its application in China Space Station
Abstract：China Space Station is the most complex manned spacecraft developed by China, in which the efficient and lightweight design of the payload supporting structure is a technical challenge encountered during the engineering development process. In order to reduce the weight of the support structure as much as possible while ensuring the service performance, an additive manufactured shell-lattice infill integrated structure is selected as its structural form, and its lightweight design is realized through topology optimization techniques. This paper summarized the design method of self-supporting lattice structure inspired by crystal symmetry for additive manufacturing; develops an optimization design approach of shell-lattice infill integrated supporting structure based on the moving morphable components (MMC) method; Taking advantage of the MMC method with explicit structural geometric parameters and the ability to obtain clear optimal force transfer paths, an additive manufacturing-oriented shell-lattice infill integrated topology optimization mathematical formulation is proposed, with the fundamental structural frequency as the constraint and the lightest weight as the optimization objective. After the optimization process, the additive manufacturing model was reconstructed by Nurbs surface based on the optimal structural force transfer path and the information of structural feature sizes on this path, which was finally fabricated by selective laser melting (SLM) process. In order to verify the effectiveness of the design, the support structure and the equipment mass simulated parts were verified by single machine vibration test. The experimental results show that the weight of the support structure is reduced by 50%, and the fundamental frequency is increased by 35% through the MMC-based topology optimization design. At present, the support structure has been successfully launched with the China space station, and the relevant equipment is operating stably in orbit. It is the first successful application and in-orbit verification of shell-lattice infill integrated structure based on the MMC topology optimization method in China's manned space field.
2022, Vol. 43 
