Macroscopic transition structures for a graded transition of properties in hybrid metal/polymer compounds - MÜGRA

“混合金属/聚合物化合物性能梯度过渡的宏观过渡结构”项目的目的是通过可变金属结构对纤维增强热塑性塑料注塑成型中的金属/聚合物界面进行可载荷设计。由于在宏观尺度范围内的过渡区设计新颖，使得材料复合的机械载荷显著提高成为可能。主要目标是通过使用过渡结构实现金属板和聚合物组件之间的渐变过渡。钢丝螺旋或机械细胞结构的可渗透结构的梯度几何设计应导致性能的梯度过渡。进一步的重点是过渡结构的可变设计，以便在不同的荷载类型下传递力。规则排列结构的材料物理模型应成为过渡区材料复合行为模拟的基础。阐述了镀锌钢板与短纤维增强聚酰胺复合材料体系中材料复合性能的新发现。为了将过渡结构连接到金属构件上，进一步开发了连接工艺，使其具有高效的应用和高负载能力。特别是，钢板上的锌层用于连接过渡结构。所述杂化材料化合物是通过插入模塑所述可渗透过渡结构而产生的。目的是研究高粘性短纤维增强热塑性熔体在通过复杂几何障碍物时的行为。采用流固耦合CFD与有限元模拟相结合的方法进行了实验与数值研究。关于（纤维增强）热塑性塑料在透水结构中的收缩行为以及短纤维增强材料在流过结构时的对齐行为（取决于透水性和工艺技术参数）的新知识被创造出来。这些过程被系统地检查并迭代地改进。与现有技术中已知的形式配合元件相比，粘附性能有望得到显著改善。金属/聚合物杂化部件中实际发生的应力表现为各个部件的复杂叠加应力状态。材料体系金属/过渡结构/聚合物的最终机械性能由合适的试样确定。

The aim of the project "Macroscopic transition structures for a graded transition of properties in hybrid metal/polymer compounds" is the load-capable design of the metal/polymer interface in injection moulding of fibre-reinforced thermoplastics by means of variable metal structures. Due to the novel design of the transition zone in the range of the macroscopic scale, significantly higher mechanical loads of the material compound are possible. The main goal is to achieve a graded transition between the sheet metal and the polymer component by the use of transition structures. The graded geometric design of a permeable structure of wire spirals or machined cell structures should result in a graded transition of properties. A further focus is on the variable design of the transition structures in order to transmit forces for different load types. The material-physical modelling of the regularly arranged structures should form the basis for the simulation of the material compound behaviour in the transition area. The new findings of the material compound behaviour are elaborated on the material system made of galvanized steel sheet and short fibre reinforced polyamide. In order to join the transition structures to the metal component, joining processes are further developed, which allow an efficient application and high load capacity. In particular, the zinc layer on the steel sheet is used for joining the transition structures. The hybrid material compounds are produced by insert moulding the permeable transition structures. The aim is to examine the behaviour of highly viscous short-fibre-reinforced thermoplastic melts when passing through complex geometrical obstacles. The investigations are carried out experimentally and numerically, by fluid-structure interaction of CFD and FEM simulation. New knowledge is created about the shrinkage behaviour of (fibre-reinforced) thermoplastics in permeable structures as well as the alignment behaviour of the short fibre reinforcement as a result of flow through the structures depending on permeability and process technology parameters. The processes are examined systematically and improved iteratively. A significant improvement of the adhesion behaviour is expected in comparison with the form fit elements known from the state of the art.The actual occurring stresses in a metal/polymer hybrid component are characterised by complex superimposed stress states of the individual components. The resulting mechanical properties of the material system metal/transition structure/polymer are determined by suitable test specimen.