Development and testing of timber-metal-hybrid materials for the side sill reinforcement of a battery electric vehicle

The development of more sustainable material solutions and the reduction of CO 2 -emissions in the production phase is one of the biggest challenges in current vehicle design. An approach to meet these requirements is the usage of renewable raw materials. Wood has excellent specific material properties comparable to aluminum and a negative CO 2 -footprint as CO 2 is stored during growth. The usage of timber for vehicle structures has already been investigated in previous projects and certain disadvantages of wood were identified. Compared to metals the elongation to fracture is low causing a brittle material behavior. Another effect is an increasing load level for compression due to compaction. In the project “SuMatHrA” the usage of a timber-steel-hybrid material for a side sill reinforcement of a battery electric vehicle is investigated. The current design of this component for different car brands is an extruded aluminum profile. The main function of this component is to protect the battery during a side crash. The lightweight wood Albasia with a density of approximately 0.3 t/m³ was used for this project. The wood was processed to laminated veneer lumber (LVL) and hybridized with a thin steel sheet. The load was applied in fiber direction causing a crushing of the LVL. To validate the developed hybrid material an aluminum profile from a current production car was used as reference. In quasi static tests it could be shown that the specific energy absorption could be increased by up to 25% compared to the extruded aluminum profile.