For those of you who didn't believe the speeding claim:


http://www.carbuzz.com/news/2014/1/5...0-MPH-7717936/




Paul Walker's Porsche Carrera GT Was Going 100 MPH + Porsche Celebrities Crash Hollywood Speeding was the factor that led to loss of control. It’s been well over a month since the tragic and horrific car crash that took the lives of actor Paul Walker and his friend Roger Rodas. The investigation is still ongoing, but more details about that sad day are beginning to come out. According to the Hollywood Reporter, whose source is the Los Angeles County Coroner’s Office, the Porsche Carrera GT the pair were driving was traveling at more than 100 mph before Rodas lost control for still "unknown reasons." - ......................

 

we all believe the speeding claim.

 

yes indeed. What a ride it must have been.

 

It's amazing what car safety is becoming, and what it still can't do.

Think about it:

Crashes into immovable barriers at 45-55 MPH are repeatably survivable. That is pretty amazing. I watched a video on YouTube where they crashed a huge 1960's chevy into the same barrier as a new Malibu (45MPH Off-set). The old chevy turned into a torn lump. The new chevy impacted, and the driver/passenger would have been uninjured.

Yet, somewhere around 70-80mph, the steel/Al or CF structures in passenger vehicles suffer catastrophic failure on impact. I wonder if they will be able to advance the safety to the point where passenger vehicles approach the survivability of a cage-equipped race car.....

 

Most of the safety of a race car is dependent on the saftey gear of the driver.
I don't think people will wear helmets, Hans devices & fire suits in their street cars.
Those things might have saved Paul and Roger.
Their car was as safe as cars get, aside from lack of electronic stability control.

 

good points!
but I think it is more reliant on engineering than that. (not to under-estimate the importance of HANS or Helmets, however)

Its been a long time since I studied any engineering principles but let me put my amateur mind to work:

I think much of crash survivability limits has to do with the way current monocoque chassis are designed. The types of steel used in the design cannot be of the same strength as formed tubes (which have an amazing range of materials and properties). Sheet steel needs to be malleable enough to be hammered in a mold. It is one of the reasons why,in many cars today, they will still have a few tubes welded inside doors or across bulkheads. (see cutaway of 997 porsche for example) At a certain level of impact, the steel in monocoques will actually tear, instead of deform. Most, if not all of the safety parameters in modern cars are based on controlled deformation. Once the tear occurs, the car disintegrates rapidly and in an uncontrolled fashion. In racing, the modern cages are almost always intact after even the most horrible crashes. In the Walker crash, the car lost all of it's integrity. The windshield hoop came back far enough to actually touch the driver. With or without helmet, it would have been a fatality. If memory serves me, the GT has a CF tub and aluminum crush zones. That would mean the CF failed?

I the future, I think the answer will be in more advanced steels/metals. Carbon fiber is coming around too, but I wonder how well that will work out. It seems rather costly at the moment and the failure of carbon fibre is usually catastrophic. It can take a lot, but then its just "gone". I remember watching videos of Titanium, woven CF and steel tubes reach failure back in school. The CF looked like it was going to go on forever, but then shazzam! It was powder. The steel got progressively weaker until it just would not return to shape. Titanium was really nice and split the difference between the 2 materials. I surely don't see us using that to make cars though!!

What do you think?

 

^ I think you are right, that a street cars cage can be made stronger and that race cars are far ahead of street cars in terms of rigidity.
Things like doors and windows, required in street cars, make it hard to achieve the same rigidity.
Dissipation of kinetic energy in modern cars is certainly better than it has been in the past.

As you stated, crash safety will continually improve with advancement of materials.
Even so, they may soon reach the limit of how much G force a passenger can survive with only a 3 point harness and w/o helmet & hans.
Race cars seem to have reached that limit already.

 

Crash safety (other than maybe fire and explosion) has a lot to do with somehow reducing the G forces imparted to the human body..

Crumple zones that reduce/absorb the energy and reduce the G forces as well as directing things that would otherwise impale you (steering columns, engines etc) or hit you crush or are directed down or away from the passengers have had a huge impact in survivability. And of course Airbags..

But yeah at some point as the velocity increases, the physics gets difficult since the kinetic energy is 1/2 Mass * velocity (squared).. Best you can do is reduce the mass (let everything break away and keep the driver in a cage).. or try to dissipate the energy slower (by crumpling or absorbing) to lower the instantaneous g-forces that scramble your innards.

what I found interesting is that when they did an aircraft crash test down in the mexican desert a couple of years ago (not the one from years ago, but more recently.. ) they found the passenger survivability (from a G-force perspective) was much better as you moved aft, simply because the fuselage crumpled and reduced the g-forces.. (I'm still not giving up my first class upgrades though

But at 100MPH hitting something rigid and static in a car.. you are probably toast... But then again over 100mph is more of a racing problem than a passenger car problem..