Identification of Forming Limits for Unidirectional Carbon Textiles in Reality and Mesoscopic Simulation
Identification of Forming Limits for Unidirectional Carbon Textiles in Reality and Mesoscopic Simulation
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单向碳织物成形极限的现实识别和细观模拟
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
P. Middendorf
中科院分区：
文献类型：
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作者：
P. Böhler;F. Härtel;P. Middendorf
在多个工程领域，碳纤维增强材料 (CFRP) 的使用正在增加。 CFRP 的最小化重量可能会降低原材料消耗，尤其是在汽车领域。 TC² 研究项目的目标是降低复合材料的成本和生产时间。为了实现更好的性能重量比并获得可接受的生产条件，对干燥单向纺织品的悬垂性和后续 RTM 工艺进行了研究。由于汽车结构的高度复杂性，成型过程具有挑战性。纺织品的角部可能会出现间隙，纤维也会起皱或弯曲。为了能够定义层或块的数量和方向，有必要了解单向材料的成型极限，并能够预测成型过程中纺织品的行为。为了定义工艺限制，在不同的拐角混合几何形状上执行多种悬垂策略。这项工作的目标是定义法兰的临界梯度，以防止出现起皱或间隙等首次故障。了解不同悬垂策略的影响也很重要。与实验测试并行，开发并提出了一种使用粗纱和缝纫线方法的细观模拟方法。它能够预测关键区域（间隙、起皱）的材料行为。可以针对两个主要方向以及纺织品的弯曲实施不同的杨氏模量和失效标准。对实验结果进行验证，目的是使用模拟方法预测纺织品的行为。
In several fields of engineering the use of carbon fibre reinforced material (CFRP) is increasing. Minimized weight due to CFRPs could lead to lower consumption of raw materials especially in the automotive area. The goal within the research project TC² is the decrease of costs and production time for composite materials. To achieve better performance to weight ratio and to get acceptable production conditions the draping of dry unidirectional textiles and a following RTM process is investigated. Due to the high degree of complexity of automotive structures the forming process is challenging. Gapping in the textile could appear at corners as well as wrinkling or flexion of the fibres. To be able to define the amount and direction of layers or patches it is necessary to know the limits of forming for unidirectional material and to be able to predict the behaviour of the textile during the forming process. For the definition of the process limits several draping strategies are performed on different corner blend geometries. The goal of that work is to define the critical gradient of the flange to get first failures such as wrinkling or gapping. It is also important to understand the influence of different draping strategies. Parallel to the experimental tests a mesoscopic simulation method using an approach with roving and sewing thread is developed and presented. It is able to predict the material behaviour in critical areas (gapping, wrinkling). Different Young’s moduli and failure criteria can be implemented for the two main directions as well as for the bending of the textile. A validation with the experimental results is performed with the aim to enable the prediction of the textile behaviour using simulation methods.