Thin-walled tubes filled with ultra-light materials have attracted much attention due to excellent energy absorption characteristics. With the development of additive manufacturing technology, it is allowed to manufacture structures with complex geometry shapes as new filled materials. In this study, complex proportional assessment (COPRAS) and discrete optimization algorithm were proposed to design and optimize the topology of thin-walled tubes filled with lattice structures. Firstly, the finite element model verified by experiment was adopted to investigate the influence of cross-sectional configurations and octet truss lattice filling distributions on crashworthiness of hybrid structures. The results show that the cross-sectional configuration has a greater effect on specific energy absorption (SEA) and the lattice filling distribution has a greater effect on peak crushing force (PCF). Then, COPRAS was used to sort the crashworthiness of hybrid structures with different topologies and select the optimal solution. It was found that C3-L4 structure had the best crashworthiness among all design schemes, indicating that the better crashworthiness can be obtained by filling the lattice in the four corner regions of tube or increase the number of cells in corner regions. Finally, the discrete optimization algorithm based on successive orthogonal arrays was adopted to further improve the crashworthiness of hybrid structure. It was found that the thin-walled tubes with different thickness had greater energy absorption capacity than those with the same thickness. Hence, the method proposed in this paper can become an effective way for topology optimization of crashworthiness.

填充超轻材料的薄壁管由于具有优异的能量吸收特性而备受关注。随着增材制造技术的发展，可以制造具有复杂几何形状的结构作为新的填充材料。在这项研究中，提出了复杂比例评估（COPRAS）和离散优化算法来设计和优化填充晶格结构的薄壁管的拓扑结构。首先，采用经过实验验证的有限元模型，研究了截面构型和八角桁架格子填充分布对混合结构耐撞性的影响。结果表明，截面构型对比能量吸收（SEA) 且晶格填充分布对峰值破碎力 ( PCF）。然后，利用COPRAS对不同拓扑结构的混合结构的耐撞性进行排序，选择最优解。发现在所有设计方案中C3-L4结构的耐撞性最好，表明通过在管的四个角区填充晶格或增加角区的单元数可以获得更好的耐撞性。最后，采用基于连续正交阵列的离散优化算法，进一步提高了混合结构的耐撞性。结果表明，不同厚度的薄壁管比相同厚度的薄壁管具有更大的能量吸收能力。因此，本文提出的方法可以成为耐撞性拓扑优化的有效途径。