ATLAS F1   Volume 6, Issue 41 Email to Friend   Printable Version

Atlas F1   The F1 Rulebook

  by Will Gray, England

In a series of articles, Will Gray delves into Formula One's rulebook and investigates the in-depth documentation that governs F1: from rules defining how the event should be run, to those restricting designers and engineers in technical areas

Thirteenth and Final Part: Road Safety Test

As weight is critical in a Formula One car, designers will take construction to its furthest extremities, and use as little material as possible to achieve the required strength. For safety, however, this is a concern, so the governing body uses both impact testing and static testing to ensure the designers aren't overexploring the limits of the rules.

The FIA requires four types of impact test (front, rear, side, and steering column) to be passed before the car can set wheels on a circuit, but once this test is done, unless there are any major modifications, the cars need take no more tests throughout the whole year. Done in the presence of an FIA technical delegate, each test is performed in a laboratory under controlled conditions, using just the parts of the car that the FIA deem to be affected by the specific impact.

In the frontal impact test, the survival cell is used, complete with a fuel tank full of water and a 75kg dummy strapped in as a driver would be. Accelerometers are attached to areas of the tub for measurement (including the driver's chest), and, fastened to a trolley to give a total weight of 780kg, the whole test structure is impacted at 50km/h. After this impact, it is essential that the survival cell was not damaged in any way; that the average deceleration of the trolley was no more than 40G; that the peak acceleration of the driver's chest was no more than 60G over 3 milliseconds; and that the average deceleration during the first 15cm of nosecone deformation was no more than 5G. Stringent, but essential figures.

A severly damaged car, with the driver suffering no injuryIn the side impact test, the relevant parts of the car are firmly attached to the ground, and a mass of 780kg is fired into it at 25km/h. To make the impact as realistic as possible, the mass must be 45cm high and 55cm wide with radiused edges, and its centre must hit the crumple zone 27.5cm above the bottom of the survival cell. However, the precise dimensions of this rule has led some teams to introduce wing-shaped crash structures in front of their sidepods. Those that use this design have found it to be more aerodynamically efficient, but some say that although this passes the written requirements, it is not in the spirit of the rules.

Again, the test structure must not damage anything but the impact absorbing structure, and the decelerations measured on the object must not exceed the FIA limits, which in this case are an average deceleration of no more than 10G, and a peak of no more than 20G for 3 milliseconds. As in the side impact test, the rear impact test requires all parts which could affect the outcome of the test (this time all those parts located behind the engine) to be fixed to the floor before the same solid object, this time traveling at 50km/h, is fired at the structure. The decelerations of the object must in this case be less than 35G on average, and 60G measured instantaneously.

The steering column is designed to crumple if the driver's head hits the steering wheel, so to check that it does, an 8kg hemispherical object (which simulates the driver's head) is fired into the appropriately mounted steering wheel at 25km/h. It must suffer an instantaneous deceleration of no more than 80G upon impact, and after the test, the steering wheel quick release mechanism is expected to work as normal.

Once these impact tests have been passed, the survival cell used must then be subjected to a number of static load tests, during which a specified load will be applied for half a minute. Although the crash test is a one-off, every survival cell built after the original will also have to undergo these static tests, but with the loads reduced by 20 percent - in case any team tries to lighten their survival cell between tests, the FIA will weigh each one and demand more crash tests if the weight varies by greater than 5%.

Firstly, the survival cell has five different static side tests, each with the load passed through a different area of the car. These comprise of: a 25kN load passing across the fuel tank; a 30kN load passing through the point where a wheel impact may occur; another load of 30kN around the point at the front of the cockpit; a 12.5kN force from beneath the fuel tank; and a cockpit squeeze of 10kN. In all of these tests, the structure must not fail, and its permanent deflection must be less than a tenth of a centimetre. Also, while it is under load, it must deflect by no more than 1.5cm (or 2cm for the cockpit squeeze). In addition to these tests, there is a nose push-off test, in which there must be no structural failure under a load of 40kN.

Diniz's Sauber upside downQuite recently, new static tests have been designed in relation to front and rear wings. In the past, some teams designed flexible mountings for the wings which, although quite a cunning move, proved to be extremely dangerous, causing several high speed crashes in testing. Unloaded, the wings were within the regulations, but as the car drove around the track, the force put on them by the air would alter their position. In the case of the front wing, downforce would increase as it flexed closer to the ground, while the rear wing would suffer from reduced drag, as the mounting flexed back to reduce the wing's angle of attack. To prevent this, the rules state that any specific part of the car which influences aerodynamics must be rigidly secured to the car, and now static weight tests for both wings ensure that nothing flexes more than 5mm under a 50kg load for the front wing, and a 140kg load for the rear wing.

Finally, there are two roll over tests required, which use multi point load application to simulate an accident. To test the primary structure, loads of 12kN lateral, 45kN longitudinal, and 60kN vertical are applied, while for the secondary structure, a large vertical load of 75kN is used. In both these tests, the deformation must be less than 5cm. However, these rules were not strict enough to cope with a double impact, and an accident last season proved, that despite all the rules, the risk in Formula One is still there. When Pedro Diniz's Sauber rolled over at the 1999 European Grand Prix, it hit the tarmac hard...twice. The roll over structure coped with the first hit, but on the second impact it collapsed, and buried Diniz's head into the gravel. He was lucky to be left alive, and the development of these safety tests continue.

Previous Parts in this Series: Part 1 | Part 2 | Part 3 | Part 4 | Part 5 | Part 6 | Part 7 | Part 8 | Part 9 | Part 10 | Part 11 | Part 12

Will Gray© 2000 Kaizar.Com, Incorporated.
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