面向制备不稳定性的多孔材料结构可靠性优化设计方法研究

With the continuous improvements of additive manufacturing technologies, the porous materials are widely used in developing processes of the major military/civilian equipment and products. However, subjected to the limitation of the preparation instability, the uncertainty effects existing in meso-mechanical models of porous materials (such as the geometric deviation in basic components and the property dispersion in substrate materials) are inevitable and extremely affect the performances of macroscopic structures, which the mismatch between the design expectation and the actual service status and even serious safety risks have to be confronted. In view of this, the meso-scale uncertainties derived from preparation instability will be taken as the research start in this project. Under the objective circumstances of poor information and insufficient data, a method of non-probabilistic reliability-based design optimization of porous material structures with consideration of procedure constraint is developed by combination of integrated design theory, non-probabilistic set theory, and structural reliability theory. This project will focus on the main problems, including the construction of uncertain meso-mechanical models and the deduction of macro properties, analysis of the bi-level non-probabilistic stiffness reliability, concurrent optimization of both meso-shape and macro-topology as well as the reliability verification techniques, etc, which aims at conquering the following three key scientific issues, namely, the reasonable description of the preparation instability, the accurate prediction of scale-span structural response bounds, and the efficiency and validity of the concurrent optimization. The achievements of this project can provide theoretical support for the current multiscale design theories, and may also play a significant promoting effect on the integrated design and manufacturing processes of high performance material structures.

随着增材制造技术的快速发展，多孔材料在重大军民装备和产品研制中应用广泛。然而，受制备不稳定性局限，多孔材料结构的细观不确定效应（组件尺寸偏差、基体属性分散等）难以避免且对宏观力学性能影响显著，导致设计预期和产品真实效能不匹配，存在严重安全隐患。鉴于此，本项目将以制备不稳定引起的细观不确定性为立足点，充分考虑工程中贫信息、少数据的客观条件，拟将材料-结构一体化设计理论、非概率集合理论及结构可靠性理论相结合，发展考虑工艺约束的多孔材料结构非概率可靠性优化技术。重点展开不确定性细观力学建模与宏观性能推演、双层级非概率刚度可靠性分析、细观形状-宏观拓扑的并发优化与可靠性验证等研究，以期在制备不稳定性合理表征、跨尺度响应界限准确预计、可靠性协同优化实施效率与置信判据等关键科学问题上实现突破。本项目将丰富和发展现有跨尺度结构设计理论，对促进高性能材料结构的设计-制造一体化进程亦起到重要的推动作用。

多孔材料是一类由贯通或封闭孔洞构成的高孔隙率网络构型材料，相比常规材料具有轻质、多功能、可设计等多种优异特征，在航空航天等军民融合领域具有广阔的应用前景。近年来，以增材制造为核心的先进制备工艺迅猛发展，带来了一种新的“自下而上”的制造理念，使得传统机加工所带来的工艺束缚被彻底打破，为细观形式复杂的高孔隙率结构设计方案提供了易操作的实现途径。然而，由于制备工艺不稳定性所衍生出的材料分散性及结构安全性问题却日益凸显，现有的一体化设计方法难以有效激发工艺不受控条件下产品的真实性，特别是在航空航天领域，飞机完整性的精细设计需求使得多孔材料结构无法突破在复杂系统主承力部件上的应用瓶颈。本项目针对上述问题，以制备不稳定引起的细观不确定性为立足点，充分考虑工程中贫信息、少数据的客观条件，将材料-结构一体化设计理论、非概率集合理论及结构可靠性理论相结合，开展了考虑制备不稳定性的高孔隙率结构不确定力学特性分析方法，细观形状/宏观拓扑的跨尺度结构可靠性并发优化方法，典型多孔材料结构设计的可靠性验证方法等方面的研究工作。项目预期发表高水平学术论文3-5篇，实际发表SCI论文17篇，皆为Q1分区，其中ESI高被引论文4篇。项目预期申请国家发明专利1-2项，实际申请发明专利10项（授权4项）、软件著作权2项。项目预期参与培养硕士、博士研究生2-3名，受本项目基金资助，实际培养研究生4名，其中博士生1名，硕士生3名。本项目研究成果应用于某型飞机上典型结构的设计，所得方案较初始设计方案的重量降低了10%以上。综上所述，本项目的研究工作建立并完善了宏/细观结构不确定力学性能推演与非概率可靠性并发优化的理论方法与验证手段，最终实现了面向制备工艺特征的高孔隙率结构安全性评估及轻量化设计，对于航空航天结构的跨尺度减重优化具有重要的理论与应用价值。