Engineers: Help me understand the energy imparted to Massa's head

Engineer here.

Here is how you calculate the energy of a projectile:

(MV^2)/450,450

The above uses the Mass in grains as is used for bullets (1 lb = 7,000 gr) and Velocity in feet per second. I heard the approx weight of the spring was 1.75 lbs (12,250 gr) and Massa was going 162 mph. But the spring wasn't going 0 mph!!! It was probably traveling at least 20 mph, so it's like a head on collision at 182 mph = 267 ft/s in actuality. Bur for the sake of argument, I'll use 162 mph = 238 ft/s.

Plug these values into the above equation and we have ~1540 ft-lbs of energy, about the same as an AK-47!!!

For comparison, a .45 auto round has about 370 to 500 ft-lbs and a .30-06 rifle about 2,800 ft-lbs. Thankfully, the spring isn't a bullet that concentrates all of its energy on a fine point and thankfully it was a glancing blow! Otherwise, Massa would be gone.

 

weight over distance multiplied by speed equals Ouch!!!!!!
I just saw the phots of Fellipe still in his helmet, Holly ****

 

Wrong. Spring was bouncing in the SAME direction as the Brawn and Ferrari were travelling - so subtract the object's speed, don't add it. Lord knows the impact was still bad enough. In fact it's quite a tribute to the helmet that Massa has survived it.

DCN

 

I again listened to the report this AM and what I heard reported was 1600 pounds of force.

 

I think this is the best Formula. And thats from an engineer in practice.

 

If they're estimating the force at 1600 lbf then that would be 51200 lbmft/sec^2 based on the conversion of 1 lbf = 32 lbmft/sec^2. The estimates of the weight of the spring that I've read is about 1.5 lbm. Since we know that F=ma that means 51200=1.5*a. Therefore we get an acceleration (desceleration) of 34133 ft/sec^2. Using an assumption that the spring is still traveling forward at about 40mph with Felipe moving at 168mph that means an effective initial velocity of 128mph which converts to 187 ft/second before impact. So I guess they estimated the impact time to be about 0.005 seconds?

Meh I'll take the path the other engineers are and say that there's just to many variables to calculate the actual forces involved and therefore it's close to a s***load in english units and a f***ton in metric.

 

Cool! Just wanted to be sure myself. Thanks for clarifying.

 

It was said and it also appears that part of the spring hit the left bodywork "bubble" on either side of the drivers head. I believe this new bodywork was instituted this year. If the spring had hit Massa without that I honestly believe he'd be gone. Also there is some give in that his helmet can move backward with the cushion behind the helmet. Spreading out the time.

In pictures his visor appears to be in pretty good condition. A very good indicator.

 

I'm sure it was the spring that caused most of the damage and then the crash just added to it. About all you can relate it to is a rock hitting your windshield while driving. Those things get spinning and hit with a lot of force. Something of the size of the spring would be like a missile. What a terrible fluke?

 

Oh?

On the vid it appeared to fly head on into Massa's helmet. If it was travelling in the same direction then it wouldn't have been as severe. It would have been quite deadly if moving head on toward him at say 80 mph!!!

I've seen a lot of talking, but few actual numbers here. Bottom line, the energy of a projectile of known mass and velocity can be calculated easily, as I showed above and got close to the reported estimate of 1,600 ft-lbs. I suppose they had a more exact weight and/or speed than I did, but that equation will calculate impact energy accurately. For the purpose of estimating energy, it is instantaneous upon impact, acceleration is not the concern. Just mass and velocity. That equation is what the firearms industry uses to rate bullet energy.

 

Not to flog an issue but the spring almost certainly did accelerate when be hit by massa's helmet, much as a baseball will decelerate the accelerate when hit by a bat. But this assumes the spring departed the helmet going forward to some degree...

 

OK, it did, but that was post impact, transfer of energy of car/Massa to spring. Didn't matter which way it went. Forces all over the place there. I'm really interested in how the skull held up. Helmet didn't fail, but debris got by part of it. Morbid interest, but skulls can take a lot more than soft tissues and vasculature in same. CT would be fascinating to look at.
Still hope Phil does OK.

 

If you look at the picture (#10 I think) you will see a lot more of the helmet including much of the back of it, especially compared to the other photos. That rapid movement of the head is what would cause a basalar skull fracture that the HANS is supposed to help prevent. If his belts held him in place his neck bore the brunt of the impact with the wall. Same injury that killed Dale, Sr. I think that FM was very luck to have survived, and without the HANS in might not have.

 

Here is the pic showing Massa and helmet;

http://www.cnn.com/2009/SPORT/07/27/f1.massa.hungary.crash.condition/index.html#cnnSTCPhoto

Picture #3

Thanks to palerider in another thread.

I would like to see a pic of the bodywork "bubble" where the spring hit.
Also I do not believe the spring itself hit Massa's head but pieces of his helmet. IMO

 

You are forgetting one important element that is making too many variables in this equation to easily solve it. The force is also inversely proportional to the surface area of the spring part that hit the helmet. It was not a cube or sphere at 1.75 lbs or whatever it weighed, but an object with a varying surface area depending on how it hit. We do not know how it hit. One of you docs with a scalpel with virtually no surface area (sharp) concentrates enough force to slice open a chest or throat with very little effort.

So all the numbers are blowing smoke. We do not know on what part of the spring it impacted or the surface area of the impacting part or receiving helmet, what the angle of incidence at impact was, how much the helmet deflected and recovered, and whether the blow was deflected by the spring tumbling before, during or after impact. Too many variables.

Great helmet, though.

Taz
Terry Phillips

 

+1 I reckon these are the best #'s we're going to get:

Perfectly valid in engineering terms

Cheers,
Ian

 

It had to travel int he same direction as Massa. How should the spring come off Barrichellos car, decelerate, come to a stop, and then accelerate towards Massa?!

 

Hmmm...sounds like the 'magic spring' theory

 

Mosely's inherent evil influence on even the physics of F1? The Ecclestone Uncertainty Principle-Bernie may have screwed with this too for greater profits?
Hope Phil continues to improve, hard to tell, but seems he is extubated. Docs seem to know their chit, mang.

 

Interesting comparison....
http://www.f1fanatic.co.uk/2009/07/28/how-hard-was-massa-hit/