3d-Shaped High-Strength Parts from Partially Delignified and Densified Wood: Introduction of the Project HolzF3

This study explores the potential of wood-based materials in sustainable lightweight automotive applications. The research focuses on overcoming the challenge of balancing complex three-dimensional design with component stiffness and strength in crash-relevant vehicle structures. The study investigates a novel approach involving partial delignification and subsequent densification of wood, previously shown to significantly enhance mechanical properties in solid wood. The HolzF3 project applies this technique to chipboard materials (strands) and small-diameter birch and beech wood, which are typically used for energy production only. By utilizing smaller semi-finished products like strands, complex three-dimensional component shapes become feasible, with densification compensating for potential loss in mechanical performance. Initial results demonstrate the effectiveness of a two-step densification process in producing high-strength wood fractions from veneers and strands derived from small-diameter birch and beech roundwood. This process increases raw material density to 0.92-1.19 g/cmB3, while significantly improving tensile strength and stiffness. Notably, densified birch veneers achieved tensile strength up to 400 MPa and stiffness up to 40 GPa, comparable to industrially available veneers. The study concludes that this approach enables the utilization of previously undervalued wood fractions in high-quality material applications, particularly in the automotive industry. This innovation not only improves product sustainability and reduces COb footprint but also creates new opportunies for sustainable value-added processes in the mobility sector.