Fraunhofer Institute for Microstructure of Materials and Systems IMWSDigital solutions for process and material simulation are becoming increasingly important as tools for plastics processing. They provide predictions on materials properties and behavior in specific manufacturing processes. However, there are currently no satisfactory simulation solutions available for compounds based on thermoplastic recyclates, 3D-printed plastic components, and UD tapes – all of which are approaches that enable particularly sustainable plastic solutions. The Fraunhofer Institute for Microstructure of Materials and Systems IMWS in Halle (Saale) is developing new material models for these areas of application in the "MikroSimPlast" project.
Simulate instead of trial and error: Data-based models make the development of new materials and products considerably more efficient. The material and energy costs for material development studies are reduced, and the time to market is shortened. Virtual simulations for optimizing plastics processing in industry are well established. However, there are still gaps, particularly for more demanding applications such as in mobility and for the use of new recyclable materials: Here, the predictions are not yet precise enough.
This is also due to the fact that changes in the material during the processing stages are not sufficiently taken into account. "Especially in the case of polymeric materials with their heterogeneous phase structures, crystallinities, or defects, the microstructure has a decisive influence on the resulting properties. However, many models have so far worked with simplifications and assumptions instead of data on the real microstructure," says Dr. Patrick Hirsch, who is leading the two-year project at Fraunhofer IMWS. An interdisciplinary team with expertise in polymer and engineering sciences, mechanical engineering, and the development and implementation of algorithms is working together on this. "We want to use our outstanding equipment for analyzing microstructure, our prior knowledge in the field of model development, and our capabilities for manufacturing and testing components to make new models available that represent real material behavior much better."
First, the materials are characterized down to the smallest detail. State-of-the-art spectroscopic and microscopic methods are used (electron microscopy, IR spectroscopy, atomic force microscopy, thermography). This in-depth understanding of materials is used to develop optimized models for virtual material and process development. The accuracy of these models is gradually optimized by validating the predicted data through real experiments on an industrial scale: In the project, components are actually manufactured and characterized in terms of their properties, and the results of these measurements are then incorporated into the further development of the new models. These are also compared with currently available simulation programs such as Digimat, ANSYS, MOLDEX, CFD simulations, or LS-Dyna and developed to be compatible with them. This will enable industrial users to easily utilize the results for application-specific material development.
The project focuses in particular on recycled compounds, components from additive manufacturing, and thermoplastic lightweight structures based on UD tapes. "In all three cases, consideration of the local microstructure is particularly important, which is why existing models are insufficient. Here we can create solutions that will also contribute to increasing the sustainability of plastic components in mobility applications," says Hirsch.
In the case of recycled materials or compounds containing recycled materials (polypropylene, polyamides, and polyester are being investigated), the focus is on developing and expanding morphological prediction models when using different fillers and reinforcing materials and varying proportions. The models targeted in the project are aimed at specific processes (extrusion, injection molding) and applications (automotive interiors).
In the production of UD tapes, particular attention is paid to accurately predicting the melt distribution within the impregnation nozzle and the impregnation behavior of selected thermoplastic matrices (polypropylene, polyamides) in combination with corresponding reinforcing fibers (glass, carbon). For additive processing, finite element method (FEM)-based models should enable the prediction of component properties depending on the materials used (the project focuses on polyamides), thus enabling the targeted further development of printing processes and the materials used.
The new solutions are aimed in particular at improving methods for developing innovative end products for new mobility. The more precise models can boost, for example, the development of materials for hydrogen tanks, interior components in cars, or large, 3D-printed components for rail vehicles, where particularly high stability and dimensional accuracy are required.
(1 September, 2025)