Understanding crash tests

Before a new design is even taken to a race, it must pass very stringent crash tests. The following sections explain what these tests include.

Frontal impact
The frontal impact involves a head-on collision at 30 mph (45 kph) into a thick steel plate set in concrete. In such an impact, the nosebox in front of the pedals is allowed only a small amount of deformation, and there must be no chassis damage beyond the nosebox. The average deceleration must not exceed 25g (25 times the force of gravity), and forces in excess of 60g are not permitted to last more than three milliseconds. This is a severe test of energy dissipation. The speed is low compared to likely impact speeds on the track, but the steel plate has zero give in it unlike metal barriers that the car would hit at the track. The absolute head-on nature also means less dissipation of impact energy than in a typical real-life impact.

Rear impact
Once the frontal test has been passed (explained in the preceding section), the same chassis then has to withstand a rear impact. This time the car remains stationary while a sled weighing the same as a fully-fuelled Formula One car is rammed into the back at 30 mph. Structural damage cannot extend beyond the rear axle line.

Roll-over test
When strictly controlled lateral (from the side), longitudinal (from in front and behind), and vertical (from above) loadings (usually measured as weight per square area) are imposed on the roll-over hoop, the hoop must not deform by more than 50mm. Any structural failure has to be limited to the top 100mm of the structure. The cars are not actually rolled over. The loadings of such an occurrence are simply simulated by the FIA’s apparatus.

Side impact test
The cars incorporate impact structures at the side of the cockpit. These must withstand pre-specified impacts and leave the internal cockpit undeformed. Specifically, a weight of 780kg travelling at 10 metres per second is impacted on the car 300mm above the “reference plane” (a strip on the car’s underside used for referencing measures) and 500mm forward of the rear edge of the cockpit. The average deceleration cannot be more than 20g, the energy absorption must be between 15 and 35 per cent of the total and a force of 80kN can be exceeded for no more than three milliseconds.

Steering column test
The steering wheel is impacted with a pre-determined force. An 8kg hemispherical weight of 165mm diameter impacts the steering wheel at seven metres per second on the same axis as the steering column. Afterwards there can be no deformation of the wheel – only of the steering column. The wheel’s quickrelease mechanism must still function perfectly.

Static load tests
A series of tests are conducted whereby a steady pressure – as opposed to a sudden impact – is applied to key parts of the car to ensure the necessary strength. These squeeze tests include cockpit sides, the rear of the chassis around the fuel cell, the gearbox, and the nosebox. For the cockpit sides a transverse load of 25kN is applied and no failure of the structure is allowed. This is then repeated at loads 20 per cent reduced each time. Deflections greater than 3mm cannot exceed 120 per cent of that obtained at 80 per cent of the first squeeze test. For the fuel tank floor a vertical load of 12.5kN is applied and the same process of repeat squeezes follow, with the same stipulation on deflections. For the cockpit rim 10kN is applied and there is a deflection limit of 20mm. For the nosebox and the rear structure a 40kN force is applied for 30 seconds and there can be no failure.