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F1 crash survivability


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#1 cedarsf1

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Posted 06 November 2017 - 15:14

Does anyone know what is the maximum survivable speed  at which an F1 car can go head on into concrete?

 

How does this compare to road cars, i.e. a 7 series BMW (which I imagine is one of the safest cars)?



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#2 Bloggsworth

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Posted 06 November 2017 - 19:43

No - And I have no intention of trying to find out...



#3 bartez1000

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Posted 06 November 2017 - 23:00

FIA mandates several crash tests of every F1 car. Frontal crash test, at unmovable object is conducted at 55km/h. All damages must be confined to nosecone. Then, there is part of monocoque before driver's feet. Is has to be at least 30cm in length. Destroying that part would absorb some speed. Then, there is footbox ahead of cockpit opening, where drivers legs are. In event of big frontal crash, it would also absorb some energy at price of removing of driver's legs. This part has about 70? cm in length, but is less thick, as it is designed to protect driver in side impacts. Finally, there is maybe 10cm from front cockpit opening to driver's hip. Survivability of driver in case of further car damages is doubtful, but not impossible. in 1977 David Purley survived crash which horribly compressed his aluminum monocoque. (as in photo)  In my opinion you can easily crash into concrete at 75kph and expect to walk away, and at 125kph? and expect to survive. This may seem low, but circuits are designed in way which removes any possibility of crashing head-on in concrete barrier. This is also a reason why there is not many cases to compare.

david-purley-lec-pre-qualifying-1977-bri



#4 GreenMachine

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Posted 07 November 2017 - 00:48

Might be worth looking at some of the old threads, istr one on Kubica's crash and also Alonso's Melbourne shunt which quoted impact Gs. 



#5 cedarsf1

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Posted 07 November 2017 - 07:00

A 125 kph (75 mph) crash into a concrete wall and survive? That is incredible. 

 

I've heard it said that an F1 car could fall out of an airplane, and if it landed straight on its nose, the driver would survive. I've wondered if that was true. 



#6 mariner

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Posted 07 November 2017 - 10:14

It is not a flippant comment but you have to define "survive"  David Puelry was terribly injured but lived. If "survive " means not being killed instantly then the speed can be very high for the  reasons of several absorbsion zones outlined above. 


Edited by mariner, 07 November 2017 - 10:17.


#7 7MGTEsup

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Posted 08 November 2017 - 14:50

I think Dave Purley's crash was a 179g impact so the human body can take a fair bit of punishment. He went from 175kph (108mph) to 0 in 66cm (26") which isn't that far if you pull out a tape measure. I think once you get to that level of impact luck becomes a huge factor in survival.



#8 munks

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Posted 08 November 2017 - 20:13

Bit surprised that Purley's neck survived 179g's. I thought the general goal from the safety folks is to keep head forces below 100g's, and of course only for very brief periods. (There are several other examples in racing besides Purley where 100+g's has been survived, but it's not recommended!)



#9 Greg Locock

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Posted 08 November 2017 - 21:40

There's several subtleties. At a slight tangent, dive tables are based on experiments done on fit young navy divers, so not surprisingly they are a bit ambitious for unfit older people. In the same way, a young strong person will probably have more neck strength than your average crash victim. Secondly, the details of how the accelerometer was mounted and the data was filtered will affect that peak reading.



#10 Tsarwash

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Posted 07 December 2017 - 19:13

FIA mandates several crash tests of every F1 car. Frontal crash test, at unmovable object is conducted at 55km/h. All damages must be confined to nosecone. Then, there is part of monocoque before driver's feet. Is has to be at least 30cm in length. Destroying that part would absorb some speed. Then, there is footbox ahead of cockpit opening, where drivers legs are. In event of big frontal crash, it would also absorb some energy at price of removing of driver's legs. This part has about 70? cm in length, but is less thick, as it is designed to protect driver in side impacts. Finally, there is maybe 10cm from front cockpit opening to driver's hip. Survivability of driver in case of further car damages is doubtful, but not impossible. in 1977 David Purley survived crash which horribly compressed his aluminum monocoque. (as in photo)  In my opinion you can easily crash into concrete at 75kph and expect to walk away, and at 125kph? and expect to survive. This may seem low, but circuits are designed in way which removes any possibility of crashing head-on in concrete barrier. This is also a reason why there is not many cases to compare.

david-purley-lec-pre-qualifying-1977-bri

Yikes, obviously the cars have been made much stronger since then, but even so, that is probably on the very edge of survivability. Obviously and tragically Ratzenberger did not survive at 195 mph. 



#11 Terry Walker

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Posted 18 December 2017 - 13:42

No, but as the awful Rastenberg crash video showed, he hit a giant piece of equipment with his helmet at high sped, and you could see the machine lift under the impact. The car went under the machine. Hence, I guess, the Halo.

 

Fortunately, very few if any F1 crashes involve running a car head-on into a large block of concrete. 


Edited by Terry Walker, 18 December 2017 - 13:42.


#12 Lee Nicolle

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Posted 25 December 2017 - 09:34

??? Terry. Roland Ratzenberger died the same meeting as Senna. 

I think you are referring to the  Bianchi one in Japan  2014 where he hit a crane. And the stupid halo would have done zero about that apart from maybe stab him with broken carbon fibre. To be honest hitting that machine at that speed was probably unsurvivable, though a simple rollcage may have helped. But I doubt it.

Carbon fibre in a structure is very strong but as a small section is not very strong and not near as strong as a chrome moly rollcage.



#13 MatsNorway

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Posted 26 December 2017 - 15:31

Have FIA specified that the halo has to be of carbon?



#14 Sisyphus

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Posted 26 December 2017 - 19:16

Survivability, or at least the peak g level, is just a function of the speed the impact starts at and how much crush distance there is.  That assumes a constant decel but typically that is what gets quoted--peak decel may be higher but then the length of time comes into it as far as what can be survived.

 

In any case, the equation is simple:  average decel in "g's" is 0.401 times the impact velocity, squared in mph divided by the crush distance in inches.  So, Purley's accident at 108 mph and a crush distance of 26 inches gives 180 g's, which 7MGTEsup quoted above.

 

That's the thing with impact--you absolutely must have something that will deform the amount given in that equation or the decel is unsurvivable.  One reason why drag racing for top fuel and funny cars shortened the track distance--300 mph and 200 g max needs 15 feet minimum... 

 

The other thing about absorbing impact energy is deformation (elongation) is everything.  You need the maximum area under the stress strain curve and that is mostly coming from high elongation.  Good old steel is ideal but brittle carbon fiber, not so much.  But it depends on the details of the design, of course.



#15 Kalmake

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Posted 30 December 2017 - 10:53

I'm always sceptical of numbers in old crashes like Purley's.

 

How did they measure the speed? Some cars did have data loggers those days, but they certainly did not have optical speed sensors. If they used rpm that could give a too high a reading due to stuck throttle.

 

How much did the barrier give? Did someone measure that? Or did they just look at the car.



#16 Sisyphus

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Posted 30 December 2017 - 17:55

I suspect the estimate of Purley's speed is reasonably accurate as the speeds at that point of the track were well known, of course.  I doubt the barrier gave too much (it was an earthen embankment with a single strand of Armco in front of it, I believe) versus the aluminum monocoque but a fair point, to be precise, you need to include the movement of the struck object in the calculations.  But if it was only 150 g's instead of 180 g's is that important?

 

I don't know about now but Purley's crushed car was in the Donnington around 1995 when I visited.



#17 Charlieman

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Posted 30 December 2017 - 18:17

I don't know about now but Purley's crushed car was in the Donnington around 1995 when I visited.

The wreck is no longer in the Donington Collection.



#18 Kalmake

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Posted 31 December 2017 - 10:48

I suspect the estimate of Purley's speed is reasonably accurate as the speeds at that point of the track were well known, of course.  I doubt the barrier gave too much (it was an earthen embankment with a single strand of Armco in front of it, I believe) versus the aluminum monocoque but a fair point, to be precise, you need to include the movement of the struck object in the calculations.  But if it was only 150 g's instead of 180 g's is that important?

 

I don't know about now but Purley's crushed car was in the Donnington around 1995 when I visited.

He would notice the stuck throttle just before the braking zone. After that point in the track his line and speed become atypical. It's still some way to the barrier from there. It's very hard to estimate how much speed was scrubbed off before the wall.

 

Or it could be less than 100g. We don't know. I think it's important to not take numbers that are estimates from unknown sources as fact.



#19 Sisyphus

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Posted 01 January 2018 - 20:44

A fair point, Kalmake, about the actual speed of impact as Purley would have been braking for all he was worth before impact although I believe this is the estimated impact speed and not the entry speed to the corner.

 

What is known is the crush distance of the monocoque and 26 inches (the figure typically quoted) and the impact velocity and average decel can have multiple solutions.  When I saw the tub on display, 26 inches seemed about right.

 

But, the ~180 g impact value for Purley's crash has been quoted many, many times in discussions of the incident.  Doesn't mean it is correct, but my point was to show where the decel value came from based on the physics.  And also to make the point that the decel depends only on the crush distance for a given impact speed.  No magic material will save the driver if the distance available to decelerate from a given speed is not adequate.

 

 

Gerry



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#20 Kalmake

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Posted 02 January 2018 - 17:04

This video is the closest in speed to the alleged 108mph I could find. Obviously a very different car, but still...

 

Skip to 1 minute



#21 gruntguru

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Posted 02 January 2018 - 23:41

So much for the crumple zone.



#22 Sisyphus

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Posted 03 January 2018 - 05:06

This video is the closest in speed to the alleged 108mph I could find. Obviously a very different car, but still...

 

Skip to 1 minute

 

The crush distance looks greater than the 26 inches the LEC sustained so the averaged g level would be corresponding less but obviously the driver would have been crushed flat inside the car.  He would not have to be concerned with dying from gross trauma due to excessive g loading.  

 

The Mythbusters car was probably twice the mass (although I suspect they may have removed the engine) so the energy to be dissipated would be proportionally greater.  Certainly the crush resistance of the front of the car would be different--a pass car isn't necessary that robust even made in steel rather than aluminum because maximizing energy absorption in a 100 mph frontal crash is not a design criteria.  This is a nonlinear buckling failure which is difficult to design for, and if the engine was removed, would not be that optimum, I think.

 

So, two different crashes--different kinetic energies, different effective stiffnesses of the vehicles, different g loadings.  Certainly both were violent crashes.



#23 Kalmake

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Posted 03 January 2018 - 11:45

(They didn't remove anything from the cars)

 

100mph to wall tests are not typically done, because they are not thought survivable. If you make the car hard enough to keep the driver from being crushed, g-forces kill him.

 

I think F1 crash tests started in the 80s. There is this clip of BT50. It had an aluminium tub reinforced with CF panels. Test speed these days is 54km/h. I don't know if it was the same then. It's about tenth of the kinetic energy compared to alleged 108mph.

 



#24 GreenMachine

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Posted 03 January 2018 - 21:11

Wow!  Look at that head movement!



#25 gruntguru

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Posted 03 January 2018 - 22:00

Reduces g forces on the brain.



#26 7MGTEsup

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Posted 18 January 2018 - 12:21

If anyone is in doubt about survivable impacts in a head on crash into concrete just look at the still from the moment of impact in Nelson Piquet's 1992 Indianapolis crash. You look at the picture and wonder where the lower half of his body is in that moment as his head is almost in contact with the wall.

 

piquetindy.jpg