3D-Printed Porous Structure and Polymer Infiltration for Fabrication of Functionally Gradient Material with Complex Shape

附加制造包括各种3D制造技术。从早期的粉末3D打印开始，商业机器现在能够使用熔融沉积建模生产热塑性塑料，使用立体平版印刷生产紫外光固化聚合物，以及使用激光烧结技术生产金属。然而，复合材料或双材料的添加制造仍然具有挑战性，特别是对于两种性能显著不同的材料，它们可以以不同的比例组合起来，产生不同的力学行为。这项研究旨在开发一种制造方法，其中利用3D打印来制作特定的脚手架结构，允许聚合物渗透并加固部件。这一新方法将为添加剂制造在快速成型、医疗保健、汽车和航空航天中的应用开发功能梯度材料、轻量化设计和增强结构。这项研究的成果将促进下一代添加剂制造技术，并为许多不同背景的学生提供教育和研究机会。本研究侧重于通过某些参数，如粘度、表面张力和聚合物渗透复合材料的力学行为来了解聚合物的渗透机理，以便定制材料的性能，包括硬度、硬度、强度和各向同性或各向异性。为此，本研究包括两个方面的工作。首先，研究小组将利用计算流体力学对渗透现象进行研究和模拟，并通过实验设计进行验证。研究结果将确定固化前包裹或排出液体聚合物的结构限制。在第二个任务中，他们将研究各种脚手架结构下复合材料力学的混合规律以及复合材料在极端载荷下的非线性行为。本研究的结果可用于建立材料分解算法。因此，在给定一组所需材料属性的情况下，该算法可用于定义支架结构和聚合物选择。

Additive manufacturing includes a variety of 3D fabrication technologies. Starting from early powder-based 3D printing, commercial machines are now capable of producing thermoplastics using fused deposition modeling, ultraviolet curable polymers using stereolithography, and metals using laser sintering techniques. However, additive manufacturing of composites or bi-materials remains challenging, particularly for two materials with significantly different properties that can be combined in various ratios to create different mechanical behaviors. This research aims to develop a manufacturing method, in which 3D printing is utilized to make specific scaffold structures, allowing polymer to infiltrate and reinforce the part. This new method will enable development of functionally gradient materials, light-weight design, and reinforced structures for applications of additive manufacturing in rapid prototyping, healthcare, automotive and aerospace. Outcomes of this research will stimulate the next-generation additive manufacturing technology and provide education and research opportunities for students of many different backgrounds. This research focuses on understanding the infiltration mechanism of the polymer through certain parameters, such as viscosity and surface tension, and mechanical behaviors of the polymer infiltrated composite in order to customize material properties, including stiffness, hardness, strength, and isotropy or anisotropy. To this end, this research includes two tasks. First, the research team will study and simulate the infiltration phenomenon using computational fluid dynamics and validate with design of experiments. The results will define the structural limits to capsulate or drain liquid polymers prior to solidification. In the second task, they will investigate the rule of mixtures for composite mechanics under a variety of scaffold structures and the non-linear behavior of the composite under extreme loads. Results from this research can be used to establish a material decomposition algorithm. This algorithm can thus be used to define scaffold structure and polymer selection given a set of desired material properties.