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

对轻量化结构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。这也适用于力引入元件。在纤维增强塑料(FRP)的轻质结构中，使用金属插件作为力引入元件可以改进设计，但可用于将销载荷引入层合板的元件通常具有简单的几何形状，并且不适合FRP的层状结构。此外，它们的集成过程主要是人工进行的，增加了生产成本。不充分的设计方法和缺乏充分分析的模型使APT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：考虑到电化学腐蚀和组合材料之间边界层的机械特性。制造技术面临着将这些材料高效、可靠地集成到现有玻璃钢工艺中的挑战，本项目的目的是从生产工艺、尺寸以及金属与玻璃钢材料之间的边界层等方面研究多层嵌件(MLI)作为复杂薄壁结构的载荷引入元件。将对在AFP工艺中集成了模块的放置金属层进行模拟和研究，以确定生产曲面结构的工艺驱动要求。采用了基于仿真的控制和监测方法，提高了过程的稳健性。详细的模拟和实验研究确定了曲率效应、相邻MLI的相互作用和多个连通MLI的影响。研究了热塑性塑料和胶粘剂系统的薄界面层降低热诱导张力的能力。分析了界面层与环氧树脂的过渡区、在金属嵌件上的应用及减张力机理。通过结合和评估各个学科开发的方法、实验试验台和原型系统，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.