Digital twin for lightweight cast structures

Cast structures offer remarkable component complexity at low production cost, making them ideal for mass-producing functionally integrated lightweight structures. In particular, ductile iron offers an optimum combination of adjustable strength, ductility and rigidity, making it ideal for lightweight design applications.

At present, the technology does not account for local differences in the material properties of ductile-iron components, which may occur due to differences in wall thickness, for instance. With this in mind, the German Federal Ministry for Economic Affairs and Climate Protection (BMWK) is supporting a project as part of its TTP Leichtbau (lightweight design technology transfer) programme. The project is named “Development of a Transferable Lightweight Design Concept to Harness Thin-walled Ductile-iron Structures’ Increased Cyclical Load Capacity Using a Digital Twin – GJSlim”. The effort is aimed at developing ultra-thin ductile iron structures with wall thicknesses below 5 mm while also ascertaining the technological influences on component design. The ultimate goal is to develop a complete concept that maximises material and structural utilisation when ductile iron is used. The consortium, which is led by RWTH Aachen University, combines different areas of expertise in the fields of casting technology, lightweight structural design and structural durability.

The experts at the Fraunhofer Institute for Structural Durability and System Reliability (LBF) have extensive experience in integrating stress-strain simulation for cyclic material properties. This allows them to obtain findings about the technological, mechanical stress-related and static influences on thin-walled ductile iron. The researchers are using simulated microstructural states to compare these with experimental findings. This, in turn, enables them to show the effects of microstructural properties and solidification time on components’ local cyclic load capacity. Developing a suitable dimensioning concept is crucial when it comes to generating the best possible estimate regarding product lifespan. The only way to make safe and reliable ultra-lightweight structures a reality is with an airtight estimate of this kind.