Rubino Felice, Carlone Pierpaolo
Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano (SA), Italy.
Polymers (Basel). 2018 Dec 24;11(1):20. doi: 10.3390/polym11010020.
In liquid composite molding processes, such as resin transfer molding (RTM) and vacuum assisted resin transfer molding (VARTM), the resin is drawn through fiber preforms in a closed mold by an induced pressure gradient. Unlike the RTM, where a rigid mold is employed, in VARTM, a flexible bag is commonly used as the upper-half mold. In this case, fabric deformation can take place during the impregnation process as the resin pressure inside the preform changes, resulting in continuous variations of reinforcement thickness, porosity, and permeability. The proper approach to simulate the resin flow, therefore, requires coupling deformation and pressure field making the process modeling more complex and computationally demanding. The present work proposes an efficient methodology to add the effects of the preform compaction on the resin flow when a deformable porous media is considered. The developed methodology was also applied in the case of Seeman's Composite Resin Infusion Molding Process (SCRIMP). Numerical outcomes highlighted that preform compaction significantly affects the resin flow and the filling time. In particular, the more compliant the preform, the more time is required to complete the impregnation. On the other hand, in the case of SCRIMP, the results pointed out that the resin flow is mainly ruled by the high permeability network.
在液体复合材料成型工艺中，如树脂传递模塑（RTM）和真空辅助树脂传递模塑（VARTM），树脂通过封闭模具中的纤维预制件，在诱导压力梯度作用下被吸入。与采用刚性模具的RTM不同，在VARTM中，通常使用柔性袋作为上半模。在这种情况下，由于预制件内部树脂压力的变化，在浸渍过程中织物会发生变形，导致增强材料厚度、孔隙率和渗透率不断变化。因此，模拟树脂流动的正确方法需要将变形和压力场耦合起来，这使得工艺建模更加复杂且计算量更大。本研究提出了一种有效方法，当考虑可变形多孔介质时，可将预制件压实对树脂流动的影响考虑在内。所开发的方法也应用于西曼复合树脂灌注成型工艺（SCRIMP）的情况。数值结果表明，预制件压实显著影响树脂流动和填充时间。特别是，预制件越柔顺，完成浸渍所需的时间就越长。另一方面，在SCRIMP的情况下，结果表明树脂流动主要由高渗透率网络控制。
