Biomimetic approaches towards lightweight composite structures for car interior parts

[Display omitted] •Bioinspired lightweight natural fibre-reinforced polypropylene panels for automotive interior fittings were developed using compression moulding.•New sandwich structure with thin, unidirectional flax fibre layers surrounding a needle felt based core.•The optimised, sustainable panel was inspired by the carapace structure of the red-eared slider and Harakeke (New Zealand Flax).•Density specific flexural properties, energy dissipation and behaviour during failure were improved significantly compared to reference plates. Due to good density specific mechanical properties and low carbon footprint, natural fibre-reinforced plastic composites made from fleeces and felts are frequently used as automotive interior parts. The industry targets further mass reduction. Following a biomimetic technology-pull approach, natural fibre-reinforced polypropylene plates with improved lightweight potential were produced using compression moulding. Best results were obtained for a sandwich structure with thin, unidirectional flax fibre layers surrounding a needle felt based core. It was inspired by the carapace structure of the red-eared slider Trachemys scripta elegans. The lay-up performed well, not only with a high density specific flexural stiffness of 2.33GPa1/3 cm3/g, strength of 9.46 MPa1/2 cm3/g, and energy dissipation but also through less abrupt failure due to an asymmetric orientation of unidirectional fibres in the two face sheets. Combined with a mass-reduced needle felt as a core, this concept displays a promising and unconventional approach for further mass reduced, sustainable interior panels used as non-visible and visible design elements in the vehicle.