How Sustainable Materials are Shaking up Motorsport

Introduction

As more and more people become acutely aware of the global warming threat, motorsport series, such as F1, have come under increasing pressure to reduce their carbon emissions. In recent years many motorsport series have introduced new regulations in an effort to enhance their environmental image, though there are calls for further action. Motorsport drives technological innovation, which eventually seeps into the wider community, so there is pressure on motorsport to set a precedent with regards to sustainability.

As composite materials provide unrivalled strength-to-weight ratios they are regularly utilised in motorsport, with more environmentally friendly composite solutions being incorporated on an increasingly frequent basis. As a composite material consists of two separate phases, there are multiple opportunities to include bioderived material – in either the fibre or resin system. Both of these options for sustainable biocomposites will be investigated in this article.

Natural Fibres

The most common way of enhancing the sustainability of a composite material is through inclusion of natural fibre reinforcement, for example flax, hemp and jute fibres.

Natural fibres are derived from plant materials, this supply can be deemed sustainable, therefore leading to a more environmentally friendly composite. The primary downside to natural fibre production though is the use of arable land, providing a direct competition to the growth of food. From an energy point of view, the production of natural fibre expends less energy than synthetic fibres, leading to a lower carbon footprint. Their end-of-life options are also good due to their ability to be biodegraded, and the higher calorific content of a natural fibre composite, if incineration is the chosen disposal method. However, it is not just their improved environmental credentials that sets them apart. They also outperform synthetic fibres in a variety of other performance criteria, many of which are pertinent to motorsport –

• Lower density than carbon and glass.
• Specific stiffness equivalent to glass.
• Significantly outperforming their synthetic counterparts in noise and vibration dampening performance.
• Reduced wear and abrasion on tooling, increasing tool life.
• Non-toxic and non-irritating, safer to handle.
• Much safer failure mode compared to carbon/glass, breaking into large blunt pieces as opposed to sharp shards. This reduces the chance of injury to the driver and likelihood of crash damage puncturing a tyre.
• Lower cost compared to carbon.

Though there are many advantages to using natural fibres, their unique make-up means that there are slight variances in processing and service life requirements compared to synthetic fibres. The main considerations when using natural fibres are the need to control the moisture ingress into the fibres, and the requirement to limit temperature exposure.

The following table summarises the main differences in properties between natural (flax), glass and carbon fibres.

As a result of the beneficial properties highlighted, natural fibres have already been incorporated into many motorsport applications, some of which are covered below.

Applications of natural fibre composites

McLaren F1 – Seat

McLaren F1 drivers could soon be racing in the comfort of a natural fibre reinforced composite seat. The ground-breaking device features Bcomp’s ampliTex™ flax fibres, incorporating powerRib™ technology for added stiffness. The composite is able to meet the mechanical property requirements, whilst exhibiting 75% lower CO₂ emissions in its production compared with a carbon fibre equivalent.

BMW i Andretti Motorsport (Formula E) – Cooling Shaft

Natural fibres have already made an impact in F1’s more environmentally friendly sister series. The BMW i Andretti Motorsport team used a flax-reinforced cooling shaft for the 2019 Formula E race season. The primary aim behind the incorporation of flax was to expose the green technology to the ultimate test, before filtering it down as an option to customers.

Porsche 718 Cayman – External Panels

The famous 24-hour race at Nürburgring in 2020 showcased a car with its external body composed entirely of natural-fibre reinforced composite materials. The Porsche 718 Cayman GT4 Clubsport MR featured panels reinforced with flax, and for the doors a sustainable balsa wood sandwich construction was adopted.

YCOM/Bcomp – Natural Fibre Crash Box

A joint partnership between YCOM and Bcomp has produced the world’s first natural fibre Front Impact Absorbing Structure (FIAS). The component was able to meet the standards exhibited by a carbon structure, with the added benefit of generating blunt pieces of broken material rather than dangerous splinters.

Other Potential Applications

Although the examples discussed so far centre around the actual race car, there are many other ways in which motorsport teams can use bioderived material, which in turn will still reduce their overall carbon footprint. Pit lane boxes and display screen surrounds are a couple of examples of off-the-car applications.

However one area which, due to its lack of visibility on a race weekend, could easily be overlooked, is tooling. All the composite parts produced for the various applications will be made using a tool. Carbon fibre prepreg is typically used to produce composite tools, leading to an excellent surface finish. However, it is possible to include natural fibre prepreg material within the construction, specifically acting as bulk-plies. Not only does this enhance the environmental sustainability of the tool, but it also provides an opportunity to reduce the weight as well. The excellent surface finish is maintained through use of carbon outer-plies, and the dimensional tolerances remain high due to the comparable coefficient of thermal expansion values for flax and carbon. An example hybrid tooling construction is shown below, incorporating our Evopreg® epoxy-based prepreg and Bcomp’s ampliTex™ flax technology.

Bioresins

Of course, the fibres aren’t the only constituent of a composite. Although, not as advanced as bioderived fibres, inroads have been made into the environmental sustainability of matrix materials, through development of bioderived resins. Bioderived epoxy and polyester resins are emerging, though typically the bio-contents of these are still quite low, and the mechanical properties can be inferior. One bioresin which is being utilised already across various areas of transport is based on polyfurfuryl alcohol (PFA), such as Evopreg PFC502. This thermosetting resin is phenolic-like in its behaviour, exhibiting excellent thermal and fire performance. A further benefit of PFA is that it is derived from crop waste, and so does not compete with food stocks. In motorsport, potential uses for PFA composites include battery enclosures, brake ducts, engine shielding, head restraints, and non-structural interior trim.

Although PFA composites have not been used in major motorsport series as of yet, they have been utilised for multiple Formula Student race cars across Europe, with applications centred around firewalls and battery enclosures, capitalising on the fire-retardant nature of this bioresin.

Summary

The growing implementation of sustainable composite materials in motorsport has been highlighted in this article. However, there is still a need for further innovation, particularly in the field of bioresins. With the biocomposites market projected to be worth 52.1 billion USD by 2026, it is expected that the industry will continue to see substantial development, with motorsport being one of the main sectors in the driving seat.

Image of Porsche 718 Cayman GT4 Clubsport MR courtesy of Dr. Ing. h.c. F. Porsche AG.

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