Gestaltung und Prozessanalyse für im Schleuderverfahren hergestellte FKV-Metall-Hohlstrukturen

Due to the increasing impact of climate change, solutions are increasingly being sought to reduce emissions of climate-damaging greenhouse gases. One possibility is the use of lightweight components that can save energy during the service life of moving systems. Hybrid tie rods or drive shafts made of fiber reinforced plastics with metallic functional or load introduction elements offer potential. Corresponding components can be produced intrinsically with continuous fiber reinforcement and thermoset matrix in a novel rotational molding process. In intrinsic hybridization, fiber reinforced plastics and metal are joined by molding or forming without the need for downstream joining processes such as bolting, riveting or bonding. Previous work has only demonstrated the general feasibility of the rotational molding process, so the mechanical strengths of the hybrid joints and the achievable cycle times for impregnation of the preform and curing of the matrix are still unknown.

In order to address these existing deficits, a solution approach is developed. This comprises the mechanical characterization of rotationally molded FRP-metal components, the creation of finite element models for design optimization and the development of a numerical mold filling simulation.
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First, tensile tests are carried out to determine suitable surface treatments for the metallic load introduction elements in order to improve adhesion between the laminate and the metal surface. For this purpose, the hybrid test specimens are divided into co-cured and form-fitted components. In addition, tensile shear tests are used to investigate different matrix systems to determine the matrix with the best adhesion properties. Based on these findings, numerical simulation models are developed for the optimization of rotationally molded FRP-metal tie rods with co-cured and form-fitted joints. For this purpose, parameterized FE models are implemented so that the geometry parameters can be changed within specified limits. A cost function is defined to evaluate the resulting stresses and determine an optimal shape. Finally, a numerical mold filling simulation is developed to determine impregnation and curing times in the rotational molding process. Suitable models for viscosity, permeability and degree of cure are selected and fitted to the material parameters used. The calculated times are validated with experimental results. This makes it possible to determine the optimum demolding time.