Digital process chain for thermoplastic structural components with local unidirectional reinforcements for aerospace applications

In recent years, struts in the aerospace industry have often been made of aluminum or in a complex thermoset FRP wound construction due to the lack of efficient manufacturing processes for thermoplastic materials for high-performance components. In addition to the lightweight construction potential, the thermoplastic fiber composites offer a high potential for sustainable aviation due to their postforming and remelting capabilities. The injection molding process offers the possibility of function integration, high flexibility in design, high production rates and short cycle times. However, the mechanical properties of injection-molded short fiber-reinforced thermoplastic (SFRTP) parts are inferior compared to continuous fiber-reinforced thermoplastic (CFRTP) parts.

In ‘InjectProfile’ project, therefore, the continuous carbon-fiber-reinforced material is used for optimized load transfer and the over-molded short-fiber-reinforced material for the integration of load introduction elements. This allows load-path- and weight-optimized thermoplastic components to be produced in short cycle times with the continuous fiber-reinforced material positioned only at main load paths, enabling a cost-effective and efficient FRP construction.

To predict the structural mechanical properties, a virtual investigation of the manufacturing process is performed using FEM analysis and process simulation. For this purpose, a digital process chain is developed within the framework of the project ‘InjectProfile’ as shown in figure 1, which extends beyond the manufacturing process to also depict a structural mechanical model. Digital twins are created for each component development stage involved, from design to manufacturing and inspection of the component’s quality. Once the component is designed and the geometry is defined, the digital process chain can be implemented in a sequence as shown in figure 1. The results from the process simulation step (for example, the fiber orientation) are transferred to the FE structural model via an intermediate 'Mapping' Step. The 'Troubleshooting Intelligence' serves as a link between simulation and reality to provide feedback on the component’s quality and appropriate process control measures.

The application advantages of a digital process chain for structural parts in aerospace are demonstrated using the tension-compression strut (component level). The developed digital process chain enables effective design and manufacturing of the parts. It aims at closing the existing gaps in current industrial practices by simulating and optimizing production systems, to increase productivity and efficiency. The results provide insights into the quality of the products under given process considerations. It also allows determining the structural integrity of the component in the event of deviating process parameters. Thereby reducing the need for extensive experiments and avoiding costly reworks of the tooling.

Short summary: Thermoplastic components with high lightweight potential can be produced at a moderate cost by continuous-fiber-reinforcement in combination with injection molded short-fiber reinforced material. The developed digital process chain links the results from process- and structural- simulations for this construction method and can thus consider process-related parameters in the component design. The influence of deviating process parameters on component’s quality can also be predicted.

The project is funded by the European Union and the State of Rhineland-Palatinate within the framework of Europäischer Fonds für regionale Entwicklung (EFRE). Furthermore, it is funded by the Bundesministerium für Wirtschaft und Klimaschutz (BMWK) within the framework of Luftfahrtforschungsprogramme LUFO V-3 and LUFO 6-1 (funding refrence 20Q1724B).

Conact:

Nithya Sindhe Narayana Rao, M.Sc.
Scientific Staff Design of Composite Structures
Leibniz-Institut für Verbundwerkstoffe GmbH
Erwin-Schrödinger-Str. 58
67663 Kaiserslautern
Telefon: +49 (0) 631/2017-273
E-Mail: nithya.sindhe@ivw.uni-kl.de

Dominic Schommer, M.Sc.
Scientific Staff Process Simulation
Leibniz-Institut für Verbundwerkstoffe GmbH
Erwin-Schrödinger-Str. 58
67663 Kaiserslautern
Telefon: +49 (0) 631/2017-151
E-Mail: dominic.schommer@ivw.uni-kl.de