Stress adapted design of load application elements for hybrid light-weight shafts manufactured by centrifugal process

轻质竖井、管道和型材通常采用纤维增强塑料（FRP）制成的空心结构。对于具有局部高功能密度的应用，FRP的使用不能产生适当的结果。例如，在传动技术中，连接和紧固元件，如齿轮、轴承或轴螺母螺纹，需要由金属制成。在多材料设计的意义上，由中空FRP基本结构和局部金属构件组成的混合材料构件符合这种要求。这种混合材料的生产是通过离心过程实现的。离心工艺是将加工好的金属元件与干燥的连续纤维结构组合在一起，放置在封闭的模具内的一种制造工艺。在模具型腔内填满液体树脂后，以高转速旋转刀具，使纤维结构由于离心力而被树脂渗透。旋转继续，直到浸渍和固化过程完成。由于流动路径短，该工艺有可能实现仅几分钟的短周期时间。在1712优先计划的第一个资助期内，开发了离心浸渍过程模型，并通过实验验证了该过程的极限。在第二个资助期，重点将放在从玻璃钢到金属的过渡领域（所谓的负荷引入领域）。由于固有的杂化——这被视为一种连接过程，其中各种材料通过初级成型连接在一起——正配合、粘附和摩擦连接的原则在负载过渡区域重叠。对于旋转对称构件，载荷传递原理对整体连接的影响迄今尚不清楚。为此，要单独检查连接，以便了解整体行为。将得到的知识运用到仿真模型中，对载荷转移区域进行优化，有针对性地调整三种原理对载荷转移的影响，从而实现减重。为了确保样品的重现性，我们建立了一个组装站，在这个组装站上，以前手工组装干纤维结构和金属元素的工作实现了自动化。装配站也可用于重复检验连接和悬垂效应对连接强度的影响。最后，对负载过渡区域优化仿真模型进行实验验证，通过验证迭代提高仿真质量。从这些结果中可以得出一个指导方针，允许用户设计由离心工艺生产的FRP金属混合部件。

Light-weight shafts, pipes and profiles are often constructed as hollow structures made of fiber-reinforced plastic (FRP). For applications with a locally high functional density the use of FRP is not yielding proper results. In transmission technology, for example, connection and fastening elements, such as gear wheels, bears or threads for shaft nuts, need to be made out of metal. In the sense of the multi-material design, hybrid components which consist of a hollow FRP basic structure and localized metal elements are relevant for such requirements. The production of such hybrids is made possible by the centrifugal process.The centrifugal process is a manufacturing process for FRP metal hybrids, in which machined metallic elements are assembled with a dry continuous fiber structure and placed in a closed mold. After the cavity of the mold has been filled with a liquid resin, the tool is rotated at high rotational speeds, so that the fiber structure is infiltrated with the resin due to the centrifugal forces. The rotation is continued until the process of impregnation and curing is completed. Due to short flow paths, this process is offering the potential to realize short cycle times of only a few minutes.In the first funding period of the priority program 1712, a process model for the impregnation in the centrifugal process was developed and experimentally validated as well as process limits. In the second funding period, the focus will be on the transition area from FRP to metal (so-called load introduction area). Due to the intrinsic hybridization - which is seen as a joining process where various materials are connected by primary shaping - the principles of positive fit, adhesion and frictional connection overlap in the load transition area. The influence of the principles for the load transfer on the overall connection is hitherto unknown for rotationally symmetrical components. For this purpose, the connections are to be examined individually, in order to understand the overall behavior. Gained knowledge is going to be used in a simulation model for the optimization of the load transition area, in which the influence of the three principles for the load transfer can be adjusted in a targeted manner and thus a weight reduction can be achieved.In order to ensure the reproducibility of samples, an assembly station is constructed on which the previously manual assembly of the dry endless fiber structure with the metallic elements is being automated. The assembly station can also be used to reproducibly examine the influence of joining and draping effects on the connection strength.Finally, the simulation model for the optimization of the load transition area is to be validated experimentally, whereby the quality of the simulation is iteratively improved by the validation. A guideline can be derived from these results, allowing users to design FRP metal hybrid parts produced by the centrifugal process.