Racecar Engineering – September 2019

SEPTEMBER 2019 http://www.racecar-engineering.com 83

Electric GT’s Tesla was the first car to feature

Bcomp’s materials, helping to achieve a 500kg

weight saving compared to the original road car

the materials themselves, not the manufacture

of the components. There are also countless

ways of calculating the carbon footprint of a

material and natural fibre materials are unlikely

to replace all the carbon components on a

racecar. However, these rough calculations

do offer an insight into how much more

environmentally friendly natural fibres can be

compared to the likes of carbon fibre.

Composites are made up of a polymer

matrix, such as epoxy or other thermosets, and

a reinforcing agent, such as a fibre. Fibres carry

load along their length, providing strength and

stiffness in one direction. Therefore, by adjusting

the orientation of the fibres the mechanical

properties can be tailored to suit the direction

of the applied load. The polymer not only acts

as an adhesive, bonding all the fibres together,

but also transfers the shear stresses and

loads between the fibres helping to optimise

the distribution of external loads across the

material. Composites are also lightweight with

a high strength to weight ratio.

The most popular composites include

carbon fibre and glass fibre. As the name

suggests, carbon fibre is made up of fibres

containing mostly carbon atoms bonded

together to form a long chain. These strands

are thinner than a human hair and they are

twisted together to form a yarn. These yarns

are then woven together to form a cloth.

Carbon fibre is around five times stronger

than steel, with twice the stiffness.

Moral fibre

Glass fibres are made from flowing molten glass

through small orifices which then solidify to

form a flexible fibre. These are then bundled

into a ‘roving’ and then woven into a cloth. High

performance natural fibres are fibres extracted

from the stem of specific plants, flax being one

of the most popular for composite materials.

Flax fibres are extracted from the linum

usitatissimum plant and are predominantly

used in linen clothing. However, flax can also be

woven and impregnated with resin to form a

composite, which can match the performance

of carbon composites in certain applications,

have a smaller environmental footprint, five

times higher vibration damping, and high radio-

transparency; but these are also more sensitive

to changes in humidity than carbon.

‘We work with flax because its supply

chain has the required maturity to provide

consistent quality over the years and it has the

best mechanical properties per unit weight

within the natural fibre group,’ says Christian

Fischer, CEO at Bcomp, a specialist in high

performance materials that are produced

from natural fibres. ‘Although these intrinsic

properties are not comparable to carbon [fibre],

if we compare to glass [fibre], we have a similar

modulus of 65GPa with almost half the density

at 1.45gcm^3. So we’re starting with a material

that has high specific stiffness.

If all the carbon fibre in a Formula 1 car was

replaced with natural fibre composites there

would be a 97.6 per cent reduction

in the CO 2 emissions produced

U

p to 85 per cent of a Formula 1 car is

made from carbon fibre composite

components, yet these only account

for roughly 20 per cent of the car’s

overall weight. With the minimum weight now

regulated to 740kg without fuel or driver, this

equates to around 148kg of carbon fibre on

each car. Research shows that the manufacture

of one tonne of carbon fibre material results in

approximately 29.5 tonnes of CO 2 emissions.

Therefore, to produce the carbon fibre required

for one F1 car, approximately 2960kg of CO 2

is released into the atmosphere. Furthermore,

carbon fibre currently lacks viable end-of-life

options, hence waste volumes are growing

rapidly, and toxic carbon dust can cause hazards

within the working environment.

Green flag

In comparison, one tonne of natural fibres has

a carbon footprint of around 0.7 tonnes. So

theoretically, if all the carbon fibre in an F1 car

was replaced with natural fibre composites, 97.6

per cent less CO 2 emissions would be produced

(103.6kg). Now, these are extremely crude

figures, which only look into the manufacture of