Maximum impact - the F1 accident reconstructed 14 Jul 2011
From a mild slap to shunts beyond human endurance, this sled at the FIA Institutes F1 Accident Reconstruction Facility reproduces Formula One accidents of every type and severity, to keep drivers safe
It is designed to recreate the forces involved in all major impacts in F1 and to measure their effect on the driver. The rig and chassis can handle impact forces of up to 100g, the equivalent of a race-car going from 100km/h to zero in one tenth of a second.
Thats pretty severe for a sled facility of this type, says the Institutes Andy Mellor, who oversaw the design of this machine. It equates to five-times the g-loads experienced by Red Bulls Mark Webber during his dramatic lift-off accident at the 2010 European Grand Prix in Valencia.
In other words, the facility can recreate impact conditions that stretch to the fastest and most devastating crashes in motor sport.
The chassis, which was donated, appropriately, by the Red Bull F1 team, can be positioned on the rig at any angle to replicate all conceivable front, side, or rear impacts. It enables FIA Institute researchers to measure accurately how well the safety systems are working and suggest improvements where necessary.
When theres an accident of particular interest, says Mellor, the FIA Institute can put a dummy in the chassis, reconstruct the crash pulse from the accident, then measure the dummy loads to see how the whole system works. We can see exactly how things like the head rest, belts, HANS device and other systems all contribute to the safety of the driver.
The crash-test dummy used in these tests is itself highly instrumented, having accelerometers and transducers located throughout its body.
Theres a whole suite of measurement channels you can use in a dummy, Mellor adds, and were using almost all of them for this work. So, as well as obvious things like chest acceleration and neck loads, were looking at other important areas such as lumbar forces and bending loads in the thoracic spine.
Its also a very different dummy from the one that would be used in a road-car test, the main difference being that the seating angle of a racing driver is reclined, so the dummy has a special moveable pelvis to reflect this unusual posture accurately.
Once the dummy is loaded into the chassis, the rig is propelled down the track at up to 100km/h. It is then stopped abruptly by a series of crush tubes which are designed to shape a pre-determined pulse.
Mellor explains: A crash-pulse is quite organic and each has a certain shape to it. Around 10 tubes are used and each has a different shape and force. You can configure them so they add up to the shape you are trying to achieve.
The tubes are made of steel and aluminium and are designed to produce a plastic behaviour, meaning that they fold rather than splinter. They vary in size, each tube being designed to withstand forces of between three and 10 tonnes, which corresponds to the different materials and objects a car may hit during an impact.
The facility can also be used to test potential new safety devices and materials. A recent test, in May 2011, examined the merits of using seat foam in single-seater cars. This is being considered as a potential solution to the shock of vertical impacts when a car is launched and lands hard, sending huge loads through the body.
Such a scenario is reminiscent of Vitaly Petrovs accident in Malaysia this year, when he hit the off-track rumble strip and the car was launched into the air. It may seem obvious that foam padding would help to minimise the chances of driver injury. But while it may help in one area of safety it can often hinder in another, which is why such tests are so important.
Mellor explains: We know that a foam attenuator can work well in the z-axis, but were concerned that if a driver has a different crash, then because they have soft material under their pelvis, it changes the way the harness works. The compression of the material could have the adverse effect of causing higher chest acceleration and bending modes of the spine.
The recent test programme looked at different thicknesses of seat foam from zero to 75mm. The test was aggressive, impacting at 70km/h and having a stopping distance of just 400mm.
This is a complex issue, says Mellor. We are working closely with Dr Terry Trammell, an Institute Fellow and medical advisor to IRL, to understand the precise injury mechanisms and the net benefit of each potential solution.
In other words, what might seem obvious to an armchair fan is often anything but. Safety is as much about finding out what you cant do, as what you can.
Republished with permission from IQ - www.institutequarterly.com