Function-driven design and simulation methods for hierarchical multi-material structures fabricated via additive manufacturing processes

增材制造（AM）是由美国材料测试协会（ASTM）定义的一类制造方法，通过添加材料通常以一层一层的方式构建3D物体。与其他制造方法相比，它们具有独特的优势，例如能够制造具有复杂形状的物体，由具有不同材料特性的异质材料制成。增材制造方法的能力极大地增强了设计人员为各种新应用探索新颖工程产品的自由度。事实上，增材制造技术通过创造具有成本效益的高价值产品，在制造业中创造了一个新的范例。然而，目前还没有一种有效的设计方法能在设计初期就鼓励功能整合。此外，现有的几何建模方法，如参数边界表示或实体建模技术，用于表示传统制造过程中相对简单的几何形状，不再能够表示增材制造设计的足够信息。迫切需要创新的设计方法和更好的计算机辅助设计工具来支持使用增材制造方法实现新产品。本课题旨在建立具有多材料分布的层次化结构设计、建模与仿真能力的功能驱动设计与仿真平台。为了实现所提出的平台，计划进行以下研究目标：1)开发面向AM的设计（DfAM）方法，以帮助设计师定义和探索由AM实现的设计空间。该方法侧重于概念设计和实施例设计的第一步。将利用信息建模技术建立增材制造知识支持，以支持新型功能驱动的零件巩固DfAM方法；2)开发几何建模和优化方法和工具，以支持不同材料分布的分层复杂结构设计。将开发混合几何建模技术，以支持快速晶格生成；3)采用实体和梁混合有限元方法开发新的分层复杂性和非均质材料组成模拟方法和工具。本课题旨在开展基础研究，以推进具有分层多尺度结构和不同材料组成的复杂物体的设计、建模和仿真。开发的方法和工具将帮助设计师在概念设计、详细设计和设计优化阶段充分利用增材制造技术提供的设计自由度。它提供了一个系统的方法与计算机辅助工具来设计创新的产品，有广泛的应用在航空航天，汽车和医疗植入/修复工业。**

Additive Manufacturing (AM) is defined by the American Society of Testing Materials (ASTM) as a class of manufacturing methods to build s 3D objects by adding materials typically in a layer-upon-layer manner. They have unique advantages over other manufacturing methods such as the capability to fabricate objects with complex shapes, made of heterogeneous materials with varying material properties. The capability of AM methods greatly enhances freedom for designers to explore novel engineered products for a variety of new applications. In fact, AM technologies have created a new paradigm in manufacturing by enabling the creation of cost effective high value products. However, there is no valid design method to encourage function integration at early design stage. Moreover, existing geometric modeling methods, such as parametric boundary representation or solid modeling techniques developed to represent relatively simple geometries for conventional manufacturing processes, are no longer capable to represent sufficient information for AM design. There is an urgent need for innovative design methods and better computer-aided design tools to support the realization of novel products using AM methods.The proposed research program aims to establish a function-drive design and simulation platform that is capable of designing, modeling, and simulating hierarchical structures with multi-material distribution. To realize the proposed platform, the following research objectives are planned:1) Development of Design for AM (DfAM) methods to aid designers in defining and exploring design spaces enabled by AM. This method focuses on conceptual design and first steps of embodiment design. Information modeling technique will be used to establish AM knowledge support to the novel function-drive DfAM method for part consolidation; 2) Development of geometric modeling and optimization methods and tools to support the design of hierarchical complex structure with varied material distribution. Hybrid geometric modeling techniques will be developed to support fast lattice generation; 3) Development of novel simulation methods and tools for hierarchical complexity and heterogeneous material composition using solid and beam hybrid finite element method. The proposed research program aims at fundamental research to advance the design, modeling and simulation of complex objects with hierarchical multi-scale structure and varied material composition. The developed method and tools will aid designers in conceptual design, detailed design, and design optimization stages to take full advantage of the design freedom provided by additive manufacturing technology. It provides a systematic approach with computer-aided tools to design innovative products that have wide applications in aerospace, automobile, and medical implant/prosthetics industry. **