Processing Fundamentals and Process Modification for Rapid Liquid Molding of High-Performance Composites

9522801 Pitchumani液态模塑采用树脂传递模塑等工艺，是一种以合理的成本制造相对大批量的复杂、高性能复合材料产品的方法。液体成型成功的一个关键是用树脂均匀而完整地填充封闭和排气的模具。由于模具内部是复合材料预制件和镶件的迷宫，流动渗透率很难建模和预测。该项目使用分析和实验研究的分形学作为描述孔结构的一种方式。这样就可以计算模具内部的渗透率。通过曲折长度和毛细管大小的分数模型，渗透率可以使用达西定律确定，因此可以使用现有的数值代码计算闭合模具中的流动。为了验证这种方法，实验装置使用了一个由三部分组成的有机玻璃模具，以及一个视频和图像处理系统来记录流动模式并确定复合材料垫子的分维。将电流通过作为预制件一部分的导电纤维是一项工艺创新，将对其进行研究，以提高固化的一致性。这项研究的影响将是改进液体复合材料成型工艺中的排气系统和均匀填充的设计，从而降低成本并增加使用这些高性能材料的机会。***

9522801 Pitchumani Liquid molding with processes like resin transfer molding, is a way to fabricate relatively high volumes of complex, high performance composite products at reasonable costs. A key to the success of liquid molding is uniform and complete filling of a closed and vented mold with resin. Because the inside of the mold is a labyrinth of composite preforms and inserts, the flow permeability is difficult to model and predict. This project uses an analytical and experimental investigation of fractals as a way to describe pore structure. This allows calculation of the permeability inside the mold. With fratal models for the tortuous length and capillary size, the permeability can be determined using Darcy's law so the flow in the closed mold can be calculated using existing numerical codes. An experimental setup to verify this approach uses a three-part Plexiglas mold, and a video and image processing system to document the flow pattern and determine the fractal dimensions of the composite mat. Passing a current through conductive fibers that are part of the preform is a process innovation that will be investigated to improve the uniformity of curing. The impact of this research will be improvements in the design of venting systems and uniform filling in liquid composite molding processes, leading to lower costs and more opportunities for use of these high performance materials. ***