增材制造使能的基于介观格状结构的零件轻量化设计理论与方法

Using less material to achieve the desired mechanical properties such as strength and stiffness is the central task of part lightweight design. Replacing solid structures with mesoscale lattice structure (MSLS) (0.1-10mm) is an additive manufacturing (AM)-enabled new way to realize part lightweight design. Traditional design method based on homogeneous periodic lattice structure leads to low structural efficiency without taking force flow into account. The research issues include: （1）Establish part force flow model which is represented by principal stress trajectory based on finite element analysis; （2）Guided by principal stress trajectory , part lattice structure is produced automatically to realize load-adapted design; (3)Considering the heterogeneous and geometry-dependent properties of AM, experiments are conducted and mathematical regression method is employed to construct the material model, and part lattice structural optimal methodology is established by coupling material model and AM constraints such as minimum diameter into lattice structure optimization model; and (4) as a result of optimization, part lattice structure that strut diameter and orientation are adapted to load magnitude and direction is obtained. The research will push forward the existing MSLS’s design theory and methodology, and possesses huge engineering application potential in aircraft, aerospace and defense industrial sectors that have high requirements for lightweight design such as high thrust-to-weight engine's blade, unmanned aerial vehicle’s fuselage and wings.

使用最少的材料达到所希望的强度等机械性能是零件设计的中心任务，以增材制造(AM)使能的特征尺寸介于0.1-10mm之间的介观格状结构（MSLS）取代实体结构是实现零件轻量化设计的新途径。针对同构MSLS存在的结构效率低以及AM的各向异性等问题，研究通过零件有限元分析建立以主应力轨迹线表示的零件力流模型；基于力流模型，借鉴有限元网格自动生成算法，以主应力轨迹线为指引进行零件MSLS与载荷的自适应设计；同时考虑AM各向异性特性以及介观尺度效应下材料性能的几何依赖性，通过物理实验并应用数学回归方法构建材料的各向异性模型，建立耦合材料模型和AM工艺约束的异构MSLS优化设计模型，通过优化得到杆件方位和直径与载荷方向和大小相适应的零件异构格状结构，进一步提高结构效率。该研究将改进MSLS现有设计理论与方法，在我国如高推重比航空发动机叶片、无人机机身机翼等关键零部件轻量化设计研发方面具有广阔应用前景。

增材制造(AM)使能的特征尺寸介于0.1-10mm之间的介观格状结构（MSLS）取代实体结构是实现零件轻量化设计的新途径。项目针对同构MSLS存在的结构效率低以及AM的各向异性等问题，研究了以主应力轨迹线为指引进行零件MSLS与载荷的自适应设计；建立了耦合材料模型和AM工艺约束的异构MSLS优化设计模型，通过优化得到了杆件方位和直径与载荷方向和大小相适应的零件异构格状结构，提高了结构效率。此外，还研究了基于应力特征和零件制造特征优化调控材料生长方向、生长路径、沉积层形态等设计变量的理论与方法；考虑应力张量与材料性能张量的耦合性，研究了基于线性或非线性切片算法迭代演进生成与PSL最大程度保持一致的材料生长模式；探索从应力空间到材料介观结构再到性能的内在映射机理，通过理论建模与实验设计建立了零件“工艺-结构-性能”模型。研究完善了增材制造现有设计和工艺规划理论与方法，促进了其在我国航空航天等关键领域的应用。项目期间培养在读博士研究生1人，在读硕士研究生5人，毕业硕士研究生4人。发表SCI/EI论文5篇；国际会议论文2篇；获授权国家发明专利5项，完成登记软件著作权1项，完成了预期研究目标。