Multi-Material Properties via Multi-Field Processing on a Single Constituent Set

这笔赠款将支持将贡献新知识的研究，使具有受控异质结构的聚合物基复合材料的加工能够在整个结构中具有空间变化的机械和电/磁性能。这项工作扩大了通过添加剂加工技术获得的材料和结构的范围，促进了科学进步和国家繁荣。几乎所有的现代材料都是由材料的混合物或复合材料组成的，这些材料可以协同作用，产生任何成分都不存在的有趣和有用的特性。这项研究着眼于通过在制造过程中施加外部电场和磁场来简化这些添加处理技术，从而导致两个相的自发内部有序。虽然最先进的多材料添加剂制造使用复杂的机械和每种材料的单独储存库，但这种工艺将通过从单一材料储存库制造具有一系列材料特性的部件来简化制造。这种工艺有能力通过控制复合材料的微结构和材料特性来制造全功能器件，从而使添加剂制造发生革命性变化。这项工作将寻找能够实现二分性的材料和工艺条件对，允许源材料在部件制造过程中根据当地需要生产刚性或顺应性、磁性或非磁性、导电或绝缘等材料。例如，这项工作将确定特定的加工技术，以从单一材料储存库在零件内产生局部导电和绝缘区域，而不是需要由绝缘聚合物包围的导电金属来制造具有集成布线的部件。通过添加剂制造开发的结构化聚合物基复合材料对包括航空航天、汽车和医疗保健在内的广泛行业至关重要，它将简化产品开发，并开辟新的应用领域，使美国经济和社会受益。这项工作的外展和教育部分将有助于扩大代表性不足群体对研究的参与，并对新兴领域的工程教育产生积极影响。本研究的目的是从实验和理论上研究和量化均匀和非均匀电磁场及其梯度在聚合物基复合材料中形成微结构的能力，这是传统的均匀和单场工艺所无法实现的。电磁辅助制造工艺可以通过将这些制造系统的复杂性降低到导致所需特性的一组工艺变量来提供一条可行的、低成本的多材料特性的路线。外部施加的电场和磁场垂直作用于未固化复合材料中嵌入的Ba6铁氧体颗粒，这是由于颗粒的平面形状和晶体c轴磁化，允许多轴控制颗粒对齐。此外，外部诱导的介电泳性和磁电性粒子-粒子相互作用允许控制粒子聚集体的排列，提供第二层次的控制。虽然介电和磁致伸展是众所周知的现象，但这项研究将为如何利用这两个场与各向异性粒子的调节相互作用来开发产生极值介电、磁和机械性能的微结构提供新的知识。研究小组将对电磁场处理进行计算多物理模拟，以预测产生的微体系结构。然后，对所得到的微结构进行有限元建模，将提供对所得到的材料特性的估计。使用预测的工艺变量进行这些复合材料的实验制造，结合一系列电磁和机械特性，将用于改进模拟并指导迭代实验和计算试验，通过多级别蒙特卡罗优化方案结束循环。这项工作的结果将提供有关工艺参数、组成、有效性能设计空间的数据，其他人可以在一般电磁加工环境中使用这些空间来制造具有定制性能的材料。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This grant will support research that will contribute new knowledge enabling the processing of polymer matrix composites with controlled heterogenous architectures that possess spatially varying mechanical and electronic/magnetic properties throughout the structure. The work extends the range of materials and structures accessible via additive processing techniques promoting the progress of science and advancing national prosperity. Almost all modern materials consist of a mixture or composite of materials which can act synergistically to produce interesting and useful properties which do not exist in any of the constituents. The research looks to the simplification of these additive processing techniques by applying external electrical and magnetic fields during the manufacturing process that leads to a spontaneous internal ordering of the two phases. While state-of-the-art multi-material additive manufacturing utilizes complex machinery and separate reservoirs for each material, this process would simplify manufacturing by fabricating parts with a range of material properties from a single material reservoir. Such processing has the capacity to revolutionize additive manufacturing by fabricating fully functioning devices through the control of the micro-architecture of the composites and hence their material properties. The work will seek out material and processing condition pairings that can achieve dichotomous properties, allowing the source material to produce materials that are stiff or compliant, magnetic or non-magnetic, conducting or insulating, etc. as needed locally during component fabrication. For example, instead of needing conducting metals surrounded by insulating polymer to fabricate parts with integrated wiring, this work will determine specific processing techniques to produce locally conductive and insulating regions within the part from the single material reservoir. Structured polymer matrix composites which are critical to a wide range of industries including aerospace, automotive, and healthcare developed through additive manufacturing would simply product development and open new application areas benefiting the U.S. economy and society. The outreach and educational components of the work will help broaden participation of underrepresented groups in research and positively impact engineering education in an emerging field. The goal of this research is to experimentally and theoretically study and quantify the ability of uniform and non-uniform electromagnetic fields and their gradients to develop micro-architectures in polymer matrix composites that have not been achieved using traditional uniform and single field processing. An electromagnetically assisted manufacturing process can provide a viable, lower-cost route to multi-material properties by reducing the complexity of these manufacturing systems down to a set of process variables that lead to desired properties. Externally applied electric and magnetic fields act orthogonally on the embedded barium hexaferrite particles within the uncured composite due to the particles' planar shape and crystallographic c-axis magnetization, allowing multi-axis control of particle alignments. Furthermore, externally induced dielectrophoretic and magnetophoretic particle-particle interactions allow control of the arrangement of aggregates of particles, providing a second hierarchical level of control. While dielectrophoresis and magnetophoresis are well known phenomena, this research will provide new knowledge of how regulated interactions of both fields with anisotropic particles can be used to develop micro-architectures that produce extremum dielectric, magnetic, and mechanical properties. The research team will perform computational multi-physics simulations of the electromagnetic field processing to predict resulting micro-architectures. Finite element modeling of the resulting micro-architectures will then provide estimates of resulting material properties. Experimental fabrication of these composites using predicted process variables, combined with an array of electromagnetic and mechanical characterization, will be used to refine simulations and to direct iterative experimental and computational trials, closing the loop with a multi-level Monto-Carlo optimization scheme. Results of this work will provide data on the process parameter, constituent, effective property design space that others may use to fabricate materials with tailored properties in a general electromagnetic processing context.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.