Three-Dimensional Multi-Scale-Modeling of the Thermoplastic PA6 In-Situ-Pultrusion

• Applicants: Professor Dr.-Ing. Christian Bonten; Professor Dr.-Ing. Peter Middendorf
• Subject Area: Plastics Engineering
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 445360388

Pultrusion is a continuous plastic processing process to manufacture continuous fiber-reinforced semi-finished products. Today, thermosets are mainly used as matrix materials because, as reac-tive monomeric starting materials, they have a much lower viscosity than thermoplastic melts and thus permit good fiber impregnation. However, a thermoplastic matrix offers various advantages compared to thermosets. Therefore, there are approaches which should enable the use of thermo-plastic matrix systems and also use the low-viscosity monomeric educts. The reactive matrix sys-tem then reacts in the heated die. Thermoplastic matrix offers several advantages. The pultrudate can be welded, formed and over-molded. In addition, the material can be recycled at the end of the product life cycle. While the pro-cessing of pultrudates with thermoset matrix systems is already very well developed and under-stood, the application of thermoplastic pultrusion still faces challenges. This is not at least due to the fact that the infiltration of the fibers by a thermoplastic matrix system and the role of the process parameters have not been sufficiently investigated, yet. From the point of view of the applicants, there is so far no suitable modeling approach that allows a holistic analysis of the pultrusion process on a micro-, meso- and macroscopic level. This would fundamentally expand the understanding of thermoplastic pultrusion. Therefore, the aim of this research project is to develop a novel and cross-scale modeling approach for the description of the fiber bundle impregnation with exact consideration of the reaction kinetics of the monomeric starting materials and the process parameters. Finally, the approach is to be verified by carrying out experiments on an existing pultrusion line. This approach should allow for a reliable statement about the impregnation of the fiber bundles and the prediction of the semi-finished product quality.The project is to be carried out as part of a cooperation between two research institutes at the Uni-versity of Stuttgart, the Institut für Kunststofftechnik and the Institut für Flugzeugbau. The compe-tencies of both research institutions are to be bundled and exploited in a targeted manner. The Institut für Kunststofftechnik will contribute its competences in the field of pultrusion processes and process simulation and the Institut für Flugzeugbau its competences in the field of fiber bundle im-pregnation and permeability prediction. An additional advantage is that the knowledge gained can be transferred very well to other infiltration processes.

• DFG Programme: Research Grants