增材制造机械组件的整体化拓扑优化设计方法研究

Holistic design of mechanical subassembly is an important approach for enhancing overall performance and improving structural efficacy by reducing weight of mechanical subassembly. This projection aims at developing topology optimization design methodology of the additive manufacturing mechanical subassembly coupling component performance, structural configuration and manufacturing constraints by combining additive manufacturing technique, topology optimization design theory and holistic design of mechanical subassembly. First, study on topology optimization of mechanical subassembly meeting functional requirements is carried out by generalizing the relationship between functionality and performance. Second, lightweight design problem of support structure for additive manufacturing mechanical subassembly is explored. The hierarchical optimization model consisting of fabrication orientation selection and support structure optimization is established. By researching on evaluation index of fabrication orientation optimized selection and optimization design and local modification of support structure, design scheme decision-making mechanism which coordinate fabrication orientation and support material usage is developed to economically and quickly design the lightweight support structures. At last, holistic design of mechanical subassembly is carried out by considering the influence mechanism of configuration and manufacturing constraints from mathematical description and solving strategy. Effective algorithm is also proposed to perform integrated optimal design of mechanical subassembly based on the topology optimization model that includes manufacturing constraints. The project research provides the design methodology support for innovative holistic design of mechanical subassembly and development of additive manufacturing technology.

机械组件整体化设计是提升组件整体性能、实现组件减重增效的重要途径。项目拟融合增材制造技术和拓扑优化设计理论，结合整体化设计思想，开展性能、构型与制造约束三者协调的增材制造机械组件整体化拓扑优化设计方法研究。首先，研究归纳机械组件的功能-性能映射关系，开展满足功能要求的机械组件整体化拓扑优化设计；其次，探讨增材制造机械组件的支撑结构轻量化设计问题，建立构建方向优选和支撑结构优化的分层优化模型，研究构建方向优选的评价指标和支撑构型的优化与局部修改，制定协调构建方向和支撑材料用量的设计方案决策机制，实现经济快速的支撑结构轻量化设计；最后，针对面向增材制造的机械组件整体化拓扑优化问题，从数学描述、求解策略方面阐述设计构型与增材制造约束的耦合影响机理，建立制造约束的拓扑优化模型，确定有效算法并实现整体化设计。项目研究成果为机械组件的整体化创新设计和增材制造技术的应用发展提供设计方法支撑。

项目结合有限元方法、拓扑优化理论、增材制造技术开展了机械组件结构的整体化设计、点阵填充轻量化设计及其有效地增材制造研究。.针对面向增材制造的机械组件整体化拓扑优化设计，提出运用装配矩阵和联接接触矩阵快速确定可整合组件的计算方法，制定机械组件整体化设计流程，实现了收紧器组件结构的整体化设计。开展了机翼检测工装整体化减重设计，提出一种能显著降低面内变形的新构型增强蜂窝，实现了增强蜂窝填充整体式工装减重22%；开展了建造方向优化，建立考虑两个打印方向的表面质量关系式，提出一种摆放稳定性指标及其计算方法，构建了考虑打印稳定性、成本和精度的多目标优化模型，整体式收紧器的建造方向优化结果验证了优化方法的有效性。.开展了多流道主动冷却结构仿真与优化。针对矩形、直排支杆、交错支杆冷却流道，采用子结构法建立流固热耦合的单流道体胞参数化模型，实验验证了模型准确性。矩形流道布局与形状优化结果表明：存在一个合适流道数来协调各性能指标，流道位置不影响压降、但影响换热性能，接近矩形的流道形状综合性能表现更好。对比研究发现三种流道中直排支杆流道在压降和换热效率指标上综合表现最好，以努塞尔数、最高温度、压降为目标的直排支杆流道支杆截面形状优化，将努赛尔数提高了33.3%，显著增强了换热效果。.建立了点阵单胞参数化模型，构造了实体单元与点阵单胞的映射关系，提出了一种快速建立实体-点阵有限元模型的填充方法，实现了点阵填充结构的高效建模。基于单胞参数化模型开展了给定变形要求的非均匀多孔材料优化设计，获得满足变形约束的蜂窝构型，实现了多孔材料结构形变可控设计。基于实体-点阵填充建模方法，开展了点阵填充复杂结构轻量化设计，采用布局优化与尺寸优化两步策略，实现了复杂结构非均匀点阵填充和轻量化设计。托架优化案例显示，点阵填充结构比实体结构减重25%。.所提方法对组件结构的整体化设计与增材制造、主动冷却流道结构设计、点阵-实体混合结构的快速建模与优化具有指导借鉴和应用价值。