The shortage of natural resources and the need to reduce energy consumption and the resulting greenhouse gas emissions are current global challenges. To meet international climate protection goals, new technical solutions are necessary. Lightweight construction plays an important role in this context, as reducing the mass of moving components decreases both energy demand and material usage. In road-based mobility, for example, lightweight design leads to lower driving resistance, which reduces fuel consumption or increases the range of battery electric vehicles.

The research group Lightweight Construction in Automobiles (LiA) focuses on developing technical solutions for lightweight vehicle design. The main areas of research include simulation, method development, and the development of materials and processes for new lightweight concepts. These can be based on individual materials such as high strength metals or fiber reinforced plastics, or on hybrid material systems, or on components produced through additive manufacturing using powder materials.

Research Focus Areas

To address the key challenges of functionality, resource efficiency, sustainability, and environmental compatibility of products and production processes in the future, a clear and structured approach to research questions is required. Research activities at LiA cover a broad range, from basic investigations of individual aspects of lightweight design to applied research for the design and validation of later processes and components. The research work at LiA is divided into three main teams.

Simulation and Method Development

The Simulation and Method Development team works on the modeling and analysis of mechanical systems, their manufacturing processes, and the evaluation of environmental impact. Depending on the level of detail, simulations are performed at the micro or macro mechanical level. For a reliable understanding of the mechanical behavior of a component concept, the focus is on the accurate definition of boundary conditions and the development of material models. This enables simulations that reflect realistic loading conditions and identify the interactions occurring in actual use cases.

To develop material models, the mechanical properties of materials such as aluminum, high strength steels, wood, carbon fiber reinforced plastics, and glass fiber reinforced plastics are characterized through experiments on the testing equipment available at the department.

The simulation methods include static implicit simulations of individual parts, modules, or complete structures. They also include explicit simulations for crash analysis, which are essential in automotive engineering. These allow prediction of stress and strain distributions within the component up to the point of failure. In parallel, the team develops and tests algorithms for damage and failure modeling. These are used to predict the initiation and progression of material damage in components and can estimate the residual strength of parts.

Another focus area in simulation is the analysis and design of joining technologies, both mechanical and adhesive, as well as the related manufacturing processes. This is important for evaluating the performance of assemblies and full vehicle structures, especially when the production method directly affects the final material properties, such as microstructure changes or strain hardening in metals during forming processes.

Validation of the simulation models is done through detailed comparisons between simulation and experimental results to ensure that the findings are accurate and applicable.

In addition to functional design and development, the team also conducts environmental impact assessments of lightweight solutions, for example through life cycle analysis. The aim is to evaluate the environmental effects of different concepts early in the development process to support material and process selection. This contributes to the development of lightweight designs that meet technical, economic, and environmental requirements.

Materials and Processes

The Materials and Processes team focuses on processing materials with high potential for lightweight applications. This potential is defined by maximizing the ratio of strength or stiffness to density. Therefore, high strength steel, aluminum, and titanium alloys as well as fiber reinforced plastics are of interest. Depending on the application, it may also be beneficial to combine different materials. Such hybrid combinations take advantage of the strengths of each material and reduce their individual weaknesses.

The analysis of production processes aims not only to improve the mechanical properties of the materials, whether individual or combined, but also to ensure energy efficient and resource saving processing. This includes specific heating techniques such as induction and conduction, or combined process steps such as in-mold assembly. These optimizations are first tested on small-scale samples and later transferred to full-size demonstrator components. Process research is supported by numerical methods such as forming simulations and filling studies. Validation of process results is done through image-based evaluation at both micro and macro levels as well as mechanical testing.

Additive Manufacturing

The focus of research in additive manufacturing is on process and component design. Key areas include process parameter development and process optimization. Mechanical property testing and microstructure analysis support improvements in quality, performance, and process efficiency.

In component design, simulations and topology optimization are used to create structures that are lightweight, strong, and efficient. Simulation allows evaluation of design variants before physical production, which saves time and reduces costs. Overall, the work in additive manufacturing helps improve the process and expand its use in mobility applications.

Equipment

The Chair of Lightweight Construction in Automobiles has various systems and process chains for producing demonstrators and components, and for measuring material parameters and part performance. A wide range of static, cyclic, and dynamic tests as well as microstructure analyses can be carried out. This includes three-axis tests with forces up to 80 KN, indentation testing at temperatures up to 800 °C, and high-speed tensile testing.

The department also operates a crash testing facility for components, where tests can be conducted at speeds up to 25 m/s and impact energies up to 31 KJ. Test data can be evaluated using high-speed 3D camera systems to measure local strain and temperature distributions during testing.

The department also uses various CAD and simulation tools such as Siemens NX, Solidworks, Abaqus, LS-Dyna, and Hyperworks. Computational models are run on the Noctua 2 high performance computing system at the University of Paderborn.