Collaborative Research: Innovations in Net-Shape Composite Fabrication through Microscale Modeling of Melt Infiltration

许多重要的复合材料都是通过熔融渗透法制备的，在这种渗透过程中，聚合物或金属被渗透到纤维预制件中。为了最大限度地减少后处理和机械加工，最好是直接从浸渍步骤制造零件，这一过程称为净成形制造。虽然数值模拟是工艺设计的关键部分，但标准模型在连续介质尺度上运行(即，底层纤维基质被视为连续介质相)。由于实际原因，这种方法是必要的，但它需要重要的经验主义来生成空间平均的本构方程和参数。此外，目前的经验技术不能有效地解释重要的微尺度现象，如纤维各向异性、润湿效应和浸渍过程中的空洞形成。在路易斯安那州立大学和杜兰大学的研究人员开展的这项合作研究项目中，最先进的微尺度建模技术将应用于浸渍过程，这将使分析能够使用第一原理进行。将进行实验，以帮助开发模型并验证其量化能力。在研究的第二阶段，微尺度模拟的结果将被放大并转移到连续尺度的模型中进行净形状制造。最终的目标是用这种多尺度的方法来取代当前方法中的经验主义，从而改进制造技术。该项目的合作性质将为本科生和研究生提供独特的学习机会，路易斯安那州立大学的研究生将参加杜兰大学研究的实验方面，两所大学的本科生都将参加路易斯安那州立大学的研究会议。此外，计划积极参加路易斯安那州少数群体参与联盟，为代表不足群体的学生提供暑期研究机会。

Many important composite materials are made by melt infiltration, in which polymers or metals are infiltrated into fibrous preforms. To minimize post-processing and machining, it is desirable to create parts directly from the impregnation step, a procedure called net-shape fabrication. While numerical simulation is a crucial part of process design, standard models operate at the continuum scale (i.e., the underlying fiber matrix is viewed as a continuum phase). This approach is necessary for practical reasons, but it requires significant empiricism to generate spatially averaged constitutive equations and parameters. Furthermore, current empirical techniques do not effectively account for important microcscale phenomena such as fiber anisotropy, wetting effects, and void formation during impregnation. In this collaborative research project conducted by researchers at Louisiana State University and Tulane University, state-of-the-art microscale modeling techniques will be applied to the impregnation process, which will allow analyses to be performed using first principles. Experiments will be performed to aid in the model development and to validate its quantitative capabilities. In a second phase of the research, results from the microscale simulations will be scaled up and transferred to continuum-scale models for net-shape fabrication. The ultimate goal is for this multiple-scale approach to replace much of the empiricism associated with current methods, thereby improving fabrication techniques. The collaborative nature of this project will provide unique learning opportunities for undergraduate and graduate students, with graduate students from LSU participating in experimental aspects of the research at Tulane, and undergraduates from both institutions being included in research meetings at LSU. In addition, active participation in the Louisiana Alliance for Minority Participation is planed to provide summer research opportunities for students from under-represented groups.