The transverse permeability of fibrous reinforcement is one of the critical parameters that govern fabrication efficiency and production quality in several liquid composite molding process variants devised to achieve transverse impregnation of fibrous reinforcements. It is difficult to precisely measure and predict the transverse permeability, because it is simultaneously affected by diverse factors, for example, the geometric features of the test mold, nesting between fabric layers, and flow‐induced compaction of the fiber bed. In this article, the saturated transverse permeability of 2D woven glass fabrics is investigated using information provided by mesostructural geometric models reproducing the real textile architecture. These models are created by micro‐CT aided geometric modeling, a recently proposed technique to analyze three‐dimensional images obtained by X‐ray microtomography. They are called “material twins” because they reproduce with assessed accuracy the geometrical configuration of the textile preform, are representative of material variability, and allow performing numerical simulations of flow or mechanical properties. Computer simulations of steady state transverse flows in material twins were carried out to evaluate the transverse permeability and compared to experiments. Issues concerning material variability due to nesting and the accuracy of transverse permeability measurements were considered and discussed. A good agreement was obtained between numerical and experimental values of transverse permeability. Both approaches show a significant influence of the number of layers considered, which can be explained by nesting between adjacent plies. Numerical simulations also illustrate how nesting significantly affects material variability.

中文翻译：

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基于材料孪生的二维玻璃纤维织物饱和横向渗透性的数值和实验研究

纤维增强材料的横向渗透性是控制制造效率和生产质量的关键参数之一，在设计用于实现纤维增强材料的横向浸渍的几种液体复合成型工艺变体中。很难精确测量和预测横向渗透率，因为横向渗透率同时受到多种因素的影响，例如测试模具的几何特征，织物层之间的嵌套以及纤维床的流致压实。在本文中，我们使用二维结构玻璃模型的信息来再现2D机织玻璃织物的饱和横向渗透性，该模型再现了真实的纺织品结构。这些模型是通过micro-CT辅助几何建模创建的，最近提出的一种技术，用于分析X射线显微断层摄影术获得的三维图像。之所以将它们称为“材料双胞胎”，是因为它们以评估的精度复制了纺织品预成型坯的几何构造，代表了材料的可变性，并允许进行流动或机械特性的数值模拟。对材料双胞胎中的稳态横向流动进行了计算机模拟，以评估横向渗透率，并与实验进行了比较。考虑并讨论了由于套料引起的材料变异性和横向渗透率测量精度的问题。横向渗透率的数值和实验值之间取得了很好的一致性。两种方法都对所考虑的层数产生了重大影响，这可以通过相邻层之间的嵌套来解释。数值模拟还说明了嵌套如何显着影响材料的可变性。