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

轻质竖井、管道和型材通常被建造为由纤维增强塑料(FRP)制成的空心结构。对于具有局部高功能密度的应用，使用玻璃钢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、轴螺母的轴承或螺纹，需要用金属制成。在多材料设计的意义上，由中空玻璃钢基本结构和局部金属元件组成的混杂构件与这种要求相关。这种混杂材料的生产是通过离心法实现的。离心法是一种制造玻璃钢金属杂化材料的工艺，加工后的金属元素与干燥的连续纤维结构组装在一起，并放置在封闭的模具中。在模具的型腔中填充液体树脂后，工具以高转速旋转，从而由于离心力而使树脂渗透到纤维结构中。继续旋转，直到浸渍和固化过程完成。在优先计划1712的第一个资助期内，建立了离心法浸渍的工艺模型，并进行了实验验证和工艺限制。在第二个资金期，重点将放在从玻璃钢到金属的过渡领域(所谓的负载引入领域)。由于固有的杂交--这被视为一种连接过程，不同的材料通过一次成形连接--正配合、粘合和摩擦连接的原则在载荷过渡区域重叠。对于旋转对称构件，荷载传递原则对整体连接的影响到目前为止还是未知的。为此，应单独检查这些连接，以便了解整体行为。将所获得的知识用于载荷转移区域的优化仿真模型中，其中可以有针对性地调整三个原则对载荷转移的影响，从而达到减轻重量的目的。为了确保样品的重现性，建立了一个装配工位，在该工位上实现了干式环形纤维结构与金属元件的自动装配。最后，对建立的荷载过渡区优化仿真模型进行了实验验证，通过验证迭代地提高了仿真质量。从这些结果可以得出一个指导方针，允许用户设计通过离心法生产的玻璃钢金属混杂零件。

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.