Energy-absorbing polyurethane crash box in the Covestro Sonnenwagen

More than 3000 kilometres through the Australian outback – as fast as possible and using only solar energy as fuel: That is the challenge that committed student teams from all over the world want to face from October 13, 2019. That is the day when the Bridgestone World Solar Challenge 2019 will kick off in Darwin, Australia. The Team Sonnenwagen from RWTH Aachen University and University of Applied Science Aachen, which is participating in the Challenger class for the first time, will also be taking part.

The students left nothing to chance when developing their solar racing car. Aerodynamics, electrical engineering, structure, chassis, even the driving strategy: everything is planned and optimized by specialized teams. Covestro, a leading supplier of innovative high-performance materials for the automotive industry, among others and which is supporting the project as main sponsor this year, is another important team member.

Team Sonnenwagen taking a break during test drives in Nuriootpa, South Australia. A crash box in the front of the solar car protects the driver in the event of a collision. It is made of the Baysafe® rigid polyurethane foam system from Covestro.

For a great result in what is probably the toughest solar race in the world, there is no way around extremely high-performance materials that make the Sonnenwagen as light and aerodynamic as possible to achieve maximum energy efficiency. That’s why the development team relies on the energy-absorbing polyurethane foam system Baysafe® from Covestro, which is used in the crash box at the front of the solar car: The Sonnenwagen should not only be as fast as an arrow, but also as safe as possible.

Safely absorbing high impact energies

The participants of the solar rally must of course be prepared for obstacles and accidents during their journey. “In fact, every team that wants to participate in the race must present a safety concept that proves how well the driver of the solar car is protected in the event of an accident,” explains Claudio Pauler, Marketing Manager Automotive at Covestro, who is monitoring the Aachen project from Leverkusen. And Baysafe® proved to be the ideal material for intelligently resolving the conflict between low weight and excellent impact resistance: The crash box foamed with Baysafe® even absorbs impact accelerations of up to 5g.

“In other words, the Baysafe® crash box offers the driver good protection under competitive conditions, even in a frontal collision,” explains Pauler. This is also confirmed by Yusuf Can Arslan, head of the Structure Working Group of the Sonnenwagen development team: “We chose Baysafe® because it is the lightest option with the highest energy absorption and the best safety features”.

Innovative material for the automotive industry

In fact, the material is not only the ideal solution for the crash box of the solar racing car from Aachen: It also cuts a fine figure in classic automobile production. Baysafe® protects vehicles, passengers and pedestrians regardless of the direction of impact and also impresses in long-term use with its outstanding dimensional stability. The polyurethane foam system can be processed in a cost-saving manner: Mounting elements can be easily foamed and supports are elegantly and quickly moulded. And, nearly incidentally, Baysafe® prevents squeaking and rattling of components over a long period of time.

The foam system is an ideal material for modern lightweight vehicle construction, which is now the focus of development work in many automotive OEMs. Low weight combined with optimum performance is exactly the argument with which the Covestro product stood out from other energy-absorbing materials in the eyes of the solar car development team.

With 2018 sales of EUR 14.6 billion, Covestro is among the world’s largest polymer companies. Business activities are focused on the manufacture of high-tech polymer materials and the development of innovative solutions for products used in many areas of daily life. The main segments served are the automotive, construction, wood processing and furniture, and electrical and electronics industries. Other sectors include sports and leisure, cosmetics, health and the chemical industry itself. Covestro has 30 production sites worldwide and employs approximately 16,800 people (calculated as full-time equivalents) at the end of 2018.