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

液体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量复杂、高性能复合材料产品的方法。液体成型成功的关键是均匀和完全填充封闭和通风的树脂模具。由于模具内部是一个由复合预制件和镶件组成的迷宫，因此渗透性很难建模和预测。这个项目使用分形的分析和实验研究作为描述孔隙结构的一种方式。这样就可以计算出模具内部的渗透性。利用弯曲长度和毛管尺寸的致命模型，可以利用达西定律确定渗透率，从而可以使用现有的数值程序计算封闭模具内的流动。验证该方法的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的分形尺寸。将电流通过预制体的导电纤维是一项工艺创新，将被研究以提高固化的均匀性。这项研究的影响将是改进通风系统的设计和液体复合成型过程中的均匀填充，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. ***