Composite Materials: F1 Applications

Question 1

Structural efficiency

Answer 1

Crashworthiness - driver and spectator safety are paramount

Stiffness - to transmit suspension loads efficiently and give good mechanical grip

High strength - small components are subjected to very high loads

Minimum weight - low centre of gravity for good handling

Good fatigue properties - F1 cars undergo very high levels of vibration & cyclical loading, with low reserves

Question 2

Materials

Answer 2

Metals
Steels
Titanium alloys
Aluminium alloys
Magnesium alloys
Tungsten

Composite/Polymers/CMC’s
Carbon Fibre, Low Modulus – UHM
Kevlar, Zylon, Dyneema
Glass fibre
Thermoset plastics - Epoxies, Cyanate Esters, BMI
Ceramic systems - heat shielding
Honeycomb - aluminium, Nomex
Foams – PMI (Rohacell)
Thermoplastics - Nylon, Delrin
PEEK - short fibre carbon and glass filled
MMC’s – only through Additive Manufacturing e.g. aluminium silicone carbide
CMC’s - carbon-carbon composites

Question 3

Construction

Answer 3

F1 cars are modular assemblies comprised of the ‘tub’, with the engine and transmission bolted onto the rear bulkhead as stressed members

The bodywork and wings are lightweight bolt-on components. These are the pieces that can often be seen to fly off in accidents. The tub is generally left undamaged in light accidents.

Chassis manufactured in sections and bonded together after curing
1mm – 3mm skins on aluminium honeycomb core

Higher stiffness/weight ration with carbon fibre and more complex shapes and compact designs possible

Front and rear suspension made from carbon composite materials - much lighter and stiffer than traditional steel suspension. But less damage-tolerant

Moulding wings and bodywork from composites allows complex shapes to be achieved in very short lead times

Question 4

Manufacturing

Answer 4

Prepregs allow rapid manufacture of a small number of parts
Materials can be stored in a freezer for a year or more until required
Other methods – RTM, infusion, etc. incur a higher tooling and design overhead
3D fabrics are banned in the regulations on cost grounds
Clean room required to minimise risk of contamination during lay up
Mould manufacture: Tooling block material manufactured from epoxy resin with fillers
Carbon moulds: taken from the tooling block pattern, good for open-moulded, bagged components and large components such as the chassis
Aluminium moulds: good for closed, one-shot moulding, stiff and accurate, modern machine tools can manufacture them quickly
Typical prepreg composite manual lay-up process – lots of peeling, sticking and manipulation of plies
Laser ply positioning reduces operator error and ensures consistency
Rohacell (closed mould manufacture with prepreg and structural foam cores) used in wing elements
Can be machined or thermoformed to the required shape
Vacuum bagging of laminated component
Autoclave curing
Wing assembly bonding: parts bonded together with high strength, tough epoxy adhesives

Question 5

TESTING

Answer 5

Non destructive tests
Ultrasound
Acoustic emission
X-ray
CAT Scan: can see thoufh air gaps, accurate and high resolution
Mechanical impendance

Regulation structural tests
The chassis has to protect the driver, the engine and other internal components
It must undergo and pass numerous static load tests and a dynamic impact test
Frontal impact test
Rear impact test
Chassis side penetration

Question 6

Common Defects

Answer 6

Delaminations – mode I, mode II, mode III
Voids/porosity
Poor consolidation – especially with foam cored, one-shot components
Disbonds
Inclusions – backing paper
Fibre/ply bridging
Ply pinching
Core bridging

Question 7

Sustainable composites

Answer 7

Flax composites currently have the best properties

Resins with bio-sourced ingredients

Question 8

3D Printing

Answer 8

often use RP techniques to produce aerodynamic components, minor structures and mould tooling for prepreg manufacture