Looking at nature is a great way to design better and stronger materials. Designers and researchers take inspiration to make stronger steel with a structure like bone, crocheted installations that look like sea urchins, artificial spider silk, etcetera. BMW Group has joined this trend with their BISS project (Bio-inspired Safety Systems), working alongside several other companies and universities. From the project, two cases of biomimicry emerged, namely a helmet inspired by the pomelo fruit and protective clothing inspired by fish and reptile scales.

If a pomelo fruit falls from a high tree, it does not split open, and the insides remain largely undamaged. In addition, the rind is extremely lightweight. These are, of course, exactly the qualities you want to have in a helmet.

The secret of the pomelo fruit lies in the fact that it is auxetic. Conventional material gives way and becomes thinner under the pressure point. Auxetic materials, on the other hand, compress and harden faster. Another characteristic of this material is that it actually becomes thicker when stretched, rather than thinner.

In the BISS project, researchers have managed to decipher the unique structure of auxetic natural protection. With newly developed methods, they managed to transfer these this characteristic to the structure of foams, specifically PUR (polyurethane). This makes it possible to produce composite textiles with a protective effect not previously achieved.

In addition to the pomelo fruit, researchers also took inspiration from the scales of fish and reptiles. These scales overlap to create a composite system that stiffens under load to provide protection against injury. Alligators’ protective armour, on the other hand, works in part by distributing force to neighbouring scales.

Initially, the aim of the research project was to analyse the tissue formation, cell structure and functioning of these protection mechanisms and explore their suitability for use in industrially manufactured products. From there, the next step was to refine the corresponding fibre composites, layer structures and fibre orientation. The project then went on to examine how functions that had previously been difficult to reconcile, like “crash protection”, “penetration resistance” and “damping”, could be combined in innovative protective systems using layering modelled on biological structures.

Prototypes designed from natural models are up to 20 per cent lighter, tougher and more stable than materials generally used today. They can be produced economically and processed for the intended purposes. The high level of functional efficiency achieved by biologically inspired protective equipment also saves material. This not only makes both product and production more sustainable, but also less expensive.

The biologically inspired products could help protect workers, for instance gloves and protective inserts. The lightweight, breathable design and flexibility of the research models mean that movement is barely restricted, which also provides an opportunity for athletic gear.

The BMW Group worked alongside Adidas, Ortema, Phoenix and Uvex, as well as the Institute of Textile Technology and Process Engineering Denkendorf, Germany, the Department of Polymer Engineering at the University of Bayreuth and the Plant Biomechanics Group of the University of Freiburg, with additional support from partners such as the company Innovationsmanufaktur in Munich. The German Federal Ministry for Education and Research subsidised the project as part of its “Technical Textiles for Innovative Applications and Products – NanoMatTextil” programme.

Images: BMW Group