Methodology for a near net shape, wrinkle-free production of textile preforms by using a segment based die draping

使用基于分段的模具悬垂技术近净形状、无皱生产纺织预成型件的方法

基本信息

批准号：
377740863
负责人：
Professor Dr.-Ing. Jürgen Fleischer
金额：
--
依托单位：
Institut für Produktionstechnik (WBK)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2017
资助国家：
德国
起止时间：
2016-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/377740863?language=en
关键词：
Methodology near net shape wrinkle

项目摘要

The shortage of energy and resources has significantly increased the importance of lightweight construction in industrial applications in the past years. One possible way of reducing weight is the use of fibre-reinforced plastics because they show particularly prominent characteristics in terms of density such as specific stiffness and specific strength. In this context, the resin transfer moulding (RTM) constitutes a promising method considering that on the one hand it allows the production of continuous fibre-reinforced plastics - awarded the highest lightweight levels - and on the other hand shows the potential of industrialisation with high volume production at one-minute intervals. Preforming within the RTM process chain has to be considered a critical process step though, since the shaping and draping of the very flexible textile fibres significantly influences the mechanical properties of the component. To ensure efficiency and competitiveness of the preforming process, the automation of different preforming technologies was investigated in many projects.The binder-forming-technology shows a great potential to reach a large-scale production. An interesting approach for automated draping is the use of segmented stamping dies. Accordingly, the textile ply stacking sequence is shaped similar to a deep drawing process by means of matrices, punches and sliders. The fixation of the layers to one another as well as the shape retention of the preforms is achieved by using a binder.To exploit the maximum potential of the draping process with segmented punches for a large number of different geometries, a systematic method for the process design is necessary. Based on a geometric analysis and a finite element draping simulation, a segmentation of the die and the sequence of the punches have to be determined. Here, adequate case distinctions, threshold values or quantitative restrictions as well as recursion or iteration regulations must be formulated and integrated into a targeted methodical scheme.The planned investigatons shall contribute to understand the mechanism during the automated preforming process using segmented punches. By following this method, design engineers shall obtain a division of dies and a sequence of the punches for nearly any shell-shaped geometry.

过去几年，能源和资源的短缺显着增加了轻质结构在工业应用中的重要性。减轻重量的一种可能方法是使用纤维增强塑料，因为它们在密度方面表现出特别突出的特性，例如比刚度和比强度。在这种情况下，树脂传递模塑（RTM）是一种很有前途的方法，因为它一方面可以生产连续纤维增强塑料（获得最高的轻量化水平），另一方面显示出工业化的潜力以一分钟为间隔进行批量生产。不过，RTM 工艺链中的预成型必须被视为关键的工艺步骤，因为非常柔韧的纺织纤维的成型和悬垂会显着影响组件的机械性能。为了确保预成型过程的效率和竞争力，许多项目对不同预成型技术的自动化进行了研究。粘合剂成型技术显示出实现大规模生产的巨大潜力。自动裁剪的一种有趣方法是使用分段冲压模具。因此，织物层堆叠序列的形状类似于通过矩阵、冲头和滑块进行的深拉工艺。通过使用粘合剂实现各层之间的固定以及预成型件的形状保持。为了利用分段冲头针对大量不同几何形状的悬垂工艺发挥最大潜力，我们采用了一种系统化的工艺方法设计是必要的。基于几何分析和有限元悬垂模拟，必须确定模具的分段和冲头的顺序。在这里，必须制定适当的案例区分、阈值或数量限制以及递归或迭代规则，并将其整合到有针对性的系统方案中。计划的研究应有助于理解使用分段冲头的自动预成型过程中的机制。通过遵循这种方法，设计工程师将获得几乎任何壳形几何形状的模具划分和冲头序列。