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Lightweight construction research for car bodies with a better climate footprint

In a joint project, research and industry are jointly testing a more environmentally friendly production of lightweight components for the automotive industry by using digital twins. This could significantly reduce the CO₂ footprint per vehicle in the future.

When it comes to cars and CO₂ emissions, we usually first focus on the exhaust fumes from internal combustion vehicles. However, the automotive industry has long since made it its mission to significantly reduce emissions along the entire value chain. Emissions should therefore be saved even during vehicle manufacturing.

The most important starting point here is car body construction, which predominantly uses newly produced aluminium (“primary aluminium”). Its production is particularly energy-intensive and causes high CO₂ emissions. At the same time, aluminium waste is generated at various points in industrial production, for example, when cutting moulded parts. Aluminium obtained from recycling (“secondary aluminium”) is considered to be a more climate-friendly alternative because it can replace primary aluminium.

^{Car body construction with recycled aluminium without compromising quality and crash safety}

However, the use of recycled aluminium in car body construction is still limited, primarily due to the fluctuating composition of the material. Due to metallic impurities, reshaping, welding, and heat treatment processes are not always consistent and often unpredictable.

In the “S3-Alu: Simulation Methods for the Evaluation of Components and Systems for Sustainable Lightweight Construction with Secondary Aluminium” project, researchers and industry are jointly testing how primary aluminium can be replaced with secondary aluminium in automotive production in a cost-effective, process-reliable, and consistent way. The CO₂ footprint per vehicle could thus be reduced by more than half.

Simulations can be used to evaluate the quality and sustainability of recycled materials. Precise process control and an adapted material selection should ultimately enable the use of recycled aluminium with the same positive mechanical and corrosion properties as primary aluminium. In the long term, this could support the decarbonisation of vehicle production – without compromising on quality or crash safety.

^{Digital twin virtually maps various compositions}

To this end, the project team is developing a digital twin that can virtually map various compositions of recycled aluminium and serve as a basis for further analyses. Using the digital twin, the project partners are evaluating the suitability of different grades of aluminium scrap for the production of new materials. Virtual modelling allows different material variants to be simulated and their behaviour tested without the need for complex physical experiments. This saves time and resources and accelerates development.

The researchers are first investigating how large the proportion of recycled aluminium in the alloy can be if the mechanical properties and quality of the final material are to be maintained. They are also evaluating the CO₂ footprint of the resulting components and analysing how different material compositions and process variants impact sustainability. Launched in April 2023, the research project is funded with €1.9 million and will run until 31 March 2026. Project partners include the Helmholtz-Zentrum hereon GmbH as the coordinating body, the Max Planck Institute for Sustainable Materials, ACCESS e.V., Volkswagen AG, Leichtmetallgießerei Bad Langensalza GmbH, and Bode - Die Tür GmbH.

The Federal Economic Affairs Ministry has been funding innovative lightweight construction projects via the Technology Transfer Programme for Lightweight Construction (TTP LB) since April 2020 and will continue to do so until 2027. The funding programme supports the transition to a climate-neutral and competitive industrial sector.