Multilayer-Inserts - Intrinsic hybrid materials for force transmission into thin-walled high performance CFRP-structures

对轻量化结构的日益增长的需求对其设计、材料和生产技术提出了重大挑战。生产和组装成本与减重本身一样，是研发的驱动力。在由纤维增强塑料（FRP）制成的轻质结构中，使用金属插入件作为力导入元件可以改进设计，但是现有的用于将销钉载荷导入层压板的元件通常具有简单的几何形状，并且不适合FRP的层压板结构。此外，它们的集成过程主要是手动的，增加了生产成本。设计方法的不足和缺乏充分分析的模型使适当解决方案的开发复杂化。在选择合适的材料时，必须考虑几个挑战：电化学腐蚀和组合材料之间边界层的机械特性。生产技术面临着将这些材料有效可靠地集成到现有FRP工艺中的挑战，本项目的目标是从生产工艺、尺寸和金属与FRP材料之间的边界层等方面研究多层插入件作为复杂薄壁结构的载荷引入元件。模拟和调查放置金属层与模块集成在AFP过程中将进行，以确定工艺驱动的要求，生产弯曲结构。基于模拟的控制和监测方法用于增加该过程的鲁棒性。详细的模拟和实验研究确定的曲率，相邻的MLI和多个连接的MLI的相互作用引起的效果的影响。研究了热塑性塑料和粘合剂系统的薄界面层降低热致张力的能力。分析了界面层与环氧树脂之间的过渡区、在金属嵌件上的应用及减张力机理。通过结合和评估每个学科开发的方法、实验测试台和原型系统，指出了新应用领域的技术潜力。

Increasing demands on lightweight structures present major challenges for their design, materials and production technology. Production and assembly costs are as much of a driver in research and development as the weight reduction itself. This applies for force introduction elements as well.In lightweight structures out of fiber-reinforced plastics (FRP), the usage of metallic inserts as force introduction elements can enable improved designs, but available elements for pin load introduction into laminates usually are of simple geometry and are not optimized for the laminar structure of FRP. Furthermore, their integration process is mainly manual, increasing the production costs. Insufficient design methods and missing models for an adequate analysis complicate the development of apt solutions. During the selection of suitable materials several challenges have to be considered: electrochemical corrosion and the mechanical characteristics of the boundary layer between the combined materials are to be taken into account. Production technology faces the challenge of integrating these materials in existing FRP-processes efficiently and reliably.The objective of this project is to research the multilayer-insert (MLI) as a load introduction element for complex thin-walled structures under the aspects of the production process, the dimensioning and the boundary layer between metal and FRP-materials. Simulations and investigations on placing metal-layers with a module integrated in an AFP process will be conducted to determine process-driven requirements for production of curved structures. A simulation based approach for controlling and monitoring is used to increase the robustness of the process. Detailed simulations and experimental investigations determine the impact of effects induced by curvature, interaction of adjacent MLI and multiple connected MLI. Thin interface layers of thermoplastics and adhesive systems are investigated regarding their capability to reduce thermal induced tension. The transition zone between the interface layer and the epoxy resin, the application on the metallic insert and the tension reducing mechanism are analyzed. The technological potential for new areas of application are pointed out by combining and evaluating the methods, experimental test benches and prototype systems developed in each discipline.