面向增材制造的汽车轻质结构拓扑优化方法研究

With the flexible degree of freedom for prototyping, additive manufacturing (AM) could offer flexible design freedom, and it could guarantee to manufacture high-performance and light-weight structures. Standard topology optimization methods could not make full use of the new freedom for configurations and manufacturing by AM, and therefore hinder the improvements of structural performances and light-weight level. Driven by high-performance and light-weight design, this research aims to develop light-weight structural topology optimization algorithm for AM and apply it to vehicle structural design. Firstly, mapping relationship is constructed between material-structure under three-dimensional light-weight configuration and its structural behaviors to efficiently calculate the structural performances. Secondly, the coupled constraints with AM and light-weight configuration are developed to ensure the material allowance and additive manufacturability. Thirdly, the design optimization model is built by using the design metric with the required performances under multiple vehicle load cases, and its dimensional reduction strategy for the optimization problem is developed to improve the design efficiency. Finally, the related algorithm is integrated and corresponding experiments are conducted to demonstrate the effectiveness. The successful completion of this project will bring the innovative design platform for light-weight structures with AM, and potentially provide technical supports to realize the higher-performance and lighter-weight vehicle structures.

增材制造特有的柔性成型自由度，能够提供更灵活的设计自由度，是制备高性能轻质结构的保障。标准的拓扑优化方法较难充分利用增材制造所赋予新的“设计-构型-制造”自由度，不利于进一步的结构性能提高与轻量水平提升。本项目拟高性能轻质结构设计为驱动，以典型汽车结构为具体验证与应用对象，开展面向增材制造的考虑轻质结构特征与增材制造工艺的拓扑优化设计理论与方法的研究。首先，建立三维轻质几何特征下的材料-结构与功能映射关系，用于开展轻质几何特征下的高效结构分析；其次，构建面向轻质几何特征和增材制造工艺的耦合约束，从而确保设计的轻质特性和增材制造性；再次，建立融合汽车多工况性能设计准则的优化模型并发展维数缩减策略，用于缩小求解规模从而提高整体设计效率；最后，进行算法集成并开展实验验证。本项目的顺利开展，将形成面向增材制造的轻质结构拓扑优化创新设计平台，有望为进一步实现汽车结构高性能轻量化设计提供技术支持。

为充分利用增材制造赋予的“设计-构型-制造”自由度，以高性能轻质汽车结构设计为驱动，发展面向增材制造的结构拓扑优化设计方法研究，从而提升结构性能与轻量化水平。项目重点从轻质拓扑构型描述、制造性工艺约束、优化模型高效求解策略及工程应用等方面展开研究。项目取得的重要进展如下：（1）发展了基于两步滤波方法的汽车轻质结构宏微观拓扑优化设计方法，并应用于新型汽车控制臂结构设计与研发；（2）发展了实体/孔隙混合填充的三明治结构拓扑优化设计方法，实现了结构关键区域的自动补强设计；（3）发展了面向增材制造的多工况结构拓扑优化设计方法，满足增材制造最大悬挂角约束与最小尺寸约束，有效保证可制造性。此外，初步研究了基于代理模型与并行架构的优化设计加速策略等。在本项目的支持下，发表《Computer Methods in Applied Mechanics and Engineering》《Structural and Multidisciplinary Optimization》《机械工程学报》《汽车工程》等期刊论文6篇，授权发明专利3项，授权软件著作权1项，并做国内外会议报告8次。项目研究成果应用于北汽新能源、上汽通用五菱、中船重工等企业与研究院所，为产品高性能创新设计提供有力的支撑。