Composites and Chassis

The temperature in an F1 cockpit can routinely reach 50 degrees centigrade, despite the car moving at 200mph. 

Composites

Modern F1 chassis are lighter and stronger than ever thanks to composite materials. One of the first major uses of a composite material in F1 was in 1966 when Bruce McLaren’s McLaren featured a chassis made of ‘Mallite’. This consisted of a layer of balsa wood sandwiched by two layers of aluminium and made for an incredibly light and stiff material. This concept is still used today except that the balsa wood has been substituted for aluminium honeycomb and the aluminium skin is today made of carbon fibre.

Carbon Fibre

Firstly, carbon fibre. In the composites industry things are done generally in layers. Each layer lies upon it’s neighbour and together they form a strong structure. In F1, a lot of these layers are made from carbon fibre and this is produced in the form of a cloth, made as the name suggests, from fibres of carbon. How the cloth is woven determines, to some degree, the component’s final physical properties. To ensure the resulting carbon fibre has optimal strength, each layer is laid a 45 degree offset to the layer beneath it. Typically a carbon fibre shell will have eight or more layers.

With a composite such as carbon fibre, it is important to remember that their great strength is available only when loaded in tension i.e. the ends of the component are being pulled apart. This is due to the fact that the fibres that are held in the resin, themselves have only strength under tensile loading. If any other loads i.e. compressive or bending loads are fed into a carbon component, it will usually fail under a much lower load than if loaded in tension.

The Chassis

The most important factor in a racecar chassis is that it must have as much torsional rigidity as possible. this means that it much be able to resist both twist and flex. The chassis must be able to twist and flex to an extent, however it should be minimised to reduce the risk of the chassis weakening (which produces poor handling) or even breaking. The more the chassis twists and flexes, the weaker the chassis becomes and the more prone it becomes to breaking. This is why chassis’s will be ‘retired’ after several races – the chassis will have lost some torsional regidity and hence need to be phased out.

The modern day race car chassis is a monocoque – this means it is a single shell that combines both the frame of the car and the bodywork. The FIA likens these monocoques to ‘survival cells’ as this is part of the car which is designed to protect the driver in the case of a crash. Extra materials are used around the monocoque – things such as crushable areas around the cockpit sides – to offer the driver a greater deal of protection. The cell itself is made from up to 12 layers of carbon fibre – this is twice as strong as steel and five times lighter.

No two teams have identical chassis, although they all follow the same basic principles. Things that may affect the chassis include the size of the fuel tank, the weight of the chassis and the downforce that can be produced. These things are likely to be tweaked from season to season and from team to team so the chassis are in a constant state of change.