Inexpensive Lightweight Construction Is Feasible

2023 Author : Hannah Pearcy | [email protected] . Last modified: 2023-06-01 01:49

Lightweight construction is and remains a key technology for numerous industries, from vehicle and aircraft technology to shipbuilding and space travel. At the same time, the weight reduction approach offers high savings potential with regard to climate-damaging emissions. But if lightweight construction is to prevail for the majority of built-in car components, the price screw has to be turned .

Reduce CO ₂ emissions by 25 percent

This is what the numerous partners in the EU project Alliance, short for "Affordable Lightweight Automobiles Alliance", did: They explored what cost savings are possible and developed corresponding technologies. Six well-known automobile manufacturers, six component and material suppliers and various research institutions were involved. The project was coordinated by Daimler and the Fraunhofer Institute for Durability and System Reliability LBF in Darmstadt. "Together we were able to show that low-cost lightweight construction is possible," says Prof. Thilo Bein, head of science management at Fraunhofer LBF.

As project secretary, he coordinated the partners, tracked results, organized meetings and the like. “With the individual components, we were able to save over 30 percent of the weight and thus reduce their share of CO ₂ emissions by 25 percent - with an increase in costs of just 2.67 euros per kilogram saved, per component, which is good for the automaker is acceptable.”If the CO ₂ balance and the energy balance are taken into account from the beginning, the costs can be reduced even further, according to the result of the project.

Reduce iteration steps in design

However, the researchers at the Fraunhofer LBF not only contributed to the project in terms of coordination, they also contributed their own research: for example in the design of the components . If new materials are used for the production of car components, parameters such as wall thickness, natural frequency of the components - which is important for noise generation - or weight have to be re-optimized.

Seminar tip

The seminar on lightweight materials in construction teaches methods, design principles and construction methods for lightweight structures. The participants get an overview of different lightweight materials, learn about criteria for the selection of materials and learn about the advantages, disadvantages and risks of the different materials.

In many cases, this is done using the finite element method: For example, the virtual fender is divided into many small units and then its physical behavior is calculated and optimized. However, these models are very complex. "At Fraunhofer LBF, we have therefore developed a parameterized model that extremely simplifies this procedure," says Bein. The principle: The experts reduce the complexity of the model, while the parameters such as weight, natural frequency or wall thickness are retained. They use this model for optimization - which is much easier - and then transfer the results back to the original finite element model. "This multi-parameter optimization can be used in the early concept phase as well as in the later detailed design,”says Bein. The researchers have already tested their method in a virtual demonstrator module for an Opel front-end component. The result: The iteration steps in the design are reduced, the desired parameters are better achieved.

Check the durability of hybrid joining processes

The Alliance project also included the development of appropriate joining processes to securely and securely connect the lightweight components: The result is 14 different joining processes . The Fraunhofer experts have brought in their expertise in fatigue testing. For example, for hybrid joining processes - rivets in combination with adhesive - they subjected component-like samples to various cyclical loads and examined how well the connections withstand this procedure. The researchers at Fraunhofer LBF carried out a further check of the operational strength on a plastic underbody from Toyota. Both tests gave good results.

“The results will flow into product development in the next few years,” Bein is certain.