Future Trends in the Development of Vehicle Bodies Regarding Lightweight and Cost

Abstract

Lightweight design has become relevant to a lot of industry sectors, due to the wish to improve the CO2 balance of their products and to save resources. To reduce the weight of a vehicle there are different approaches to lightweight design, e.g. material substitution or lightweight construction types. These existing approaches are reaching their limits with conventional materials. For this reason lightweight materials like fibre-reinforced plastics are becoming more and more popular. However, these materials are very cost intensive. Therefore, these materials are generally used, in sports cars or in premium vehicles. In order to solve the conflict between vehicle costs and weight reduction, new lightweight approaches have to be developed for mass production. The opportunities of new materials can only be provided for a large group of customers through new approaches. One such approach is to combine fibre-reinforced plastics with the existing metallic materials. This is called multi-material or hybrid design. In this approach, the advantages of the two types of material are used for a specific application. Only then the lightweight potential can be used effective and at reasonable cost. For a vehicle, the multi-material design can be used in particular for designing the body in white. Here, almost every component can be considered by the new lightweight approach. Hybrid materials, for example, can increase the stiffness and reduce the weight of a rocker at the same time. For this the load cases of the rocker need to be analysed for which the load frequencies and amplitudes are needed. Also the life expectancy has to be determined in order to design a component with thin-walled sections as well as a minimal safety factor. Afterwards the material combination of the hybrid material is determined with respect to the load cases. Generally the fibre-reinforced plastics are placed in areas with tensile stress. Vice versa metallic materials are placed in areas with compressive stress. For designing the components ideally direct load should exist. In this case, the maximum potential for lightweight design can be used. The new lightweight approach will be developed within the Open Hybrid LabFactory together with research institutes and industrial companies. For this purpose, we gratefully thank the Federal Ministry of Education and Research for funding the research project.