The good formability of textile composite materials over complex mold geometries is one of the reasons to make their use expanding in various modern industries. However, different defects in these reinforcements could have occurred during the forming step in the manufacturing process. The defects are arising for many reasons; some are related to the fabric itself and others related to the draping parameters. Understanding the textile structure mechanics and draping behavior is essential to choose the proper reinforcement as well as to attain better simulation. Fabric wrinkles and local out-of-plane bucking of yarns were the fundamental defects in focus. The main objective of this part of the project was to experimentally investigate and compare the draping behavior of six commercially available glass fabrics from the same category of warp-knitted non-crimp fabrics (WKNCFs). The tested fabrics included two stitching patterns: tricot and chain. Also, they were relatively heavy with approximate mass per square meter. A double-dome punching test was performed to implement draping for each fabric; then, the defects were detected and characterized. Punching load-displacement curves were also recorded. In addition, a defect code was designated for the main defects to characterize forming defects at the meso-macroscopic scale. The structure and the number of fabric axes, stacking sequence, and stitching pattern all contribute to defect formation during draping. The studied configurations in this paper can help in studying the simulation of deformed technical fabric and provide a method to minimize and even eliminate the draping defects.

中文翻译：

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基于双圆顶悬垂几何的玻璃经编无卷曲织物起皱行为表征与分析

纺织复合材料在复杂模具几何形状上的良好成型性是使其在各种现代工业中使用扩大的原因之一。然而，在制造过程的成型步骤中，这些增强件可能会出现不同的缺陷。产生缺陷的原因有很多；有些与织物本身有关，有些与悬垂参数有关。了解纺织品结构力学和悬垂行为对于选择合适的增强材料以及获得更好的模拟至关重要。织物褶皱和纱线的局部平面外翘曲是重点关注的基本缺陷。该项目这部分的主要目标是通过实验研究和比较来自同一类别的经编非卷曲织物 (WKNCF) 的六种市售玻璃织物的悬垂行为。测试的织物包括两种缝合图案：经编和链条。此外，它们相对较重，每平方米的质量约为。进行双圆顶冲孔试验，对每种织物进行悬垂；然后，检测和表征缺陷。还记录了冲压载荷-位移曲线。此外，为主要缺陷指定了缺陷代码，以在细观宏观尺度上表征成形缺陷。织物轴的结构和数量、堆叠顺序和针迹图案都有助于悬垂过程中的缺陷形成。