Collaborative Research: Controlling the Microstructure for Improved Mechanical Properties of Large-scale Polymer Composite Structures Made by Big Area Additive Manufacturing

合作研究：控制微观结构以改善大面积增材制造制成的大型聚合物复合结构的机械性能

• 批准号: 2055628
• 负责人: Douglas Smith
• 金额: $ 37.82万
• 依托单位: Baylor University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-03-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2055628&HistoricalAwards=false
• 关键词: Collaborative; Research; Controlling; Microstructure; Improved

This grant supports research that contributes to new knowledge related to a manufacturing process, thus promoting the progress of science, national prosperity, and national defense. Additive manufacturing, more commonly known as three-dimensional printing, is a method of making virtually any shape from a digital computer model. Although desktop three-dimensional printers have become quite popular, they are often limited to smaller objects without sufficient strength for structural applications. This research focuses on a relatively new class of additive manufacturing that is capable of making large-scale structures such as full-size cars and houses. This project conducts fundamental research to better understand big area additive manufacturing (BAAM) of extruded carbon-fiber reinforced polymer materials to produce higher strength components that can be used in the automotive, aerospace, energy, construction and defense sectors. This is a collaborative research effort between two universities that exposes a wide and diverse group of students, including women and minorities, to new manufacturing technologies and provide opportunities to engage in hands-on activities that encourage them to pursue a career in STEM-related fields.While the development of big area additive manufacturing (BAAM) of large-scale polymer structures has moved quickly, a basic understanding of the unique microstructure within an extruded fiber-reinforced polymer composite has not kept pace. The majority of recent efforts to improve the mechanical performance of 3D-printed materials has focused on interfacial properties and addressing meso-structural defects, such as voids between beads due to incomplete filling. However, there are significant opportunities for improving the mechanical performance of 3D printed structures by controlling the internal microstructure of the extruded bead. Specifically, the goal of this research is to maximize the mechanical performance of an extruded polymer composite by controlling the size, orientation, and distribution of reinforcing fibers and voids that define its internal microstructure. This is accomplished by altering the flow path and resulting shear strain fields within the single-screw extruder and optimizing processing parameters such as flow rate, pressure, and temperature profile. Research tasks seek to establish new finite element models for deposition flow as polymer melt passes through the screw and nozzle, in addition to constitutive models defined by differential equations that provide unique insight into fiber orientation, void formation, fiber breakage and particle migration during processing. The resulting knowledge and database of material properties enable the printing of tailored microstructures within BAAM parts and components.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.

该基金支持有助于与制造过程相关的新知识的研究，从而促进科学进步，国家繁荣和国防。增材制造，通常被称为三维打印，是一种从数字计算机模型制造几乎任何形状的方法。虽然桌面三维打印机已经变得相当流行，但它们通常仅限于较小的物体，没有足够的强度用于结构应用。这项研究的重点是一种相对较新的增材制造技术，它能够制造大型结构，如全尺寸的汽车和房屋。该项目进行基础研究，以更好地了解挤压碳纤维增强聚合物材料的大面积增材制造（BAAM），以生产可用于汽车，航空航天，能源，建筑和国防部门的更高强度部件。这是两所大学之间的一项合作研究，让包括女性和少数族裔在内的广泛而多样化的学生群体接触到新的制造技术，并提供参与实践活动的机会，鼓励他们在stem相关领域从事职业。虽然大规模聚合物结构的大面积增材制造（BAAM）发展迅速，但对挤出纤维增强聚合物复合材料内部独特微观结构的基本理解却没有跟上步伐。最近，提高3d打印材料机械性能的大部分努力都集中在界面性能和解决细观结构缺陷上，例如由于填充不完全而导致的珠粒之间的空隙。然而，通过控制挤出头的内部微观结构来改善3D打印结构的机械性能有很大的机会。具体来说，本研究的目标是通过控制增强纤维的尺寸、方向和分布，以及决定其内部微观结构的空隙，来最大限度地提高挤出聚合物复合材料的机械性能。这是通过改变单螺杆挤出机内的流动路径和由此产生的剪切应变场，以及优化加工参数（如流量、压力和温度剖面）来实现的。研究任务是建立新的有限元模型，用于聚合物熔体通过螺杆和喷嘴时的沉积流动，以及由微分方程定义的本构模型，这些本构模型提供了对加工过程中纤维取向、空隙形成、纤维断裂和颗粒迁移的独特见解。由此产生的材料特性知识和数据库可以在BAAM零件和组件中打印定制的微结构。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。