LeiFu

Intelligent lightweight construction through functional integration

In particular, fiber-reinforced plastics (FRP), due to their specific structure and manufacturing processes — beyond mere weight reduction in the context of lightweight construction — offer excellent opportunities for integrating additional functions. Weight reduction potential can be realized both through the direct integration of functions into structural components and through the exploitation of secondary lightweight construction potential. In this context, the greatest challenge for the functionalization of FRP structural components currently lies in the efficient, industrially feasible integration of functions into the components themselves and the parallel development of process-reliable, automated, and cost-effective manufacturing processes.

New approaches to breaking the weight spiral

The project “LeiFu – Intelligent Lightweight Construction through Functional Integration,” presented in this publication, therefore aimed to develop new approaches—based on functional integration—to break the weight spiral in the automotive sector while tapping into the unique potential of fiber-reinforced plastics. With a view to large-scale automotive production, the project is being implemented in such a way that the cost-saving effects of functional integration minimize any additional costs to the overall system resulting from the comparatively expensive use of fiber-reinforced plastics.

The publication traces the path from determining the requirements for a real automotive component through the development and evaluation of approaches to functionalization to concept development and the implementation phase. For this purpose, functionalities are first developed and their integration possibilities are demonstrated using various individual function demonstrators. Mechanical functions (e.g. crash, NVH), thermal functions (e.g. heating, insulation), sensory functions (e.g. structural health monitoring, detection of fluid leakage) and electrical functions (e.g. contactless charging) are integrated in substructures. Based on technology evaluations and functional tests, these are brought together in a functionally integrated floor module.

Following the integration of the individual technologies into the floor module, this was further optimized in terms of function, weight, costs and manufacturability. At the same time, the individual technologies were optimized with regard to the overall system. The key points here were a further reduction in weight, optimization of strength and rigidity with regard to the material volume used, such as through weight-optimized wall thickness distribution and load path optimization, as well as fibre surface optimization.

The results of LeiFu are tried and tested, highly functionally integrated lightweight FRP structures suitable for large-scale production. Compared to the functionally equivalent reference structure with 74 parts and a total weight of 113.2 kg, the LeiFu base has a significant reduction in weight and telecount. The final structure weighs 70.5 kg with 28 parts. This corresponds to a weight saving of 38% with a simultaneous reduction in the number of parts of 62%.