irishfan

Two Comments:

Electrical power - as a volunteer firefighter, I can assure you that power is stored long enough for the air bags to deploy even if there is a direct hit to the electrical system. We train to disconnect the car battery and then still treat the system as active for another 15-20 minutes.

Air bag deployment - when air bags deploy, they do so in a violent, explosive manner. They are designed to deploy only if absolutely necessary, but very quickly when they are needed. A car can take quite a hit (and have lots of damage) without triggering the airbags. This is desirable, because if the airbags deploy unnecessarily, they can cause a great deal of injury to the person or persons sitting in front of or next to them. Nothing in these pictures leads me to believe that they should have deployed, but I am sure Nissan will let us know more about it after they investigate the incident.

Mike821

What do you mean nothing?

WayneTN

What irishfan is saying (if I may interpret what I think he said) is that it appears to him that, although there was severe damage to the side of the car, the G-forces may have been low enough, due to proper crumple-zone design, so as to not trigger the side air bags.

Notice, also, the front crumple zone. It deformed the entire front-end, but left the passenger compartment safe - just like engineers designed it.

The side collision looks like a significant impact to me, but I'm not an expert. Obviously the issue requires more study by Nissan and accident specialists.

Anyway, glad the driver will be OK. Take my word for it: very lucky here....maybe Someone was watching out for him....

WayneTN

Vlad

tell me if I'm wrong, but I thougt that side airbag sole purpose is to soften hit from the door and window to passenger head and body. As I see it all parts of cabin could be intact and look nice and new, if made of tought enough metal. But passenger could be dead at the same time. Because due to inertion window saddenly accelerated toward his head. And you can't see what G forces was from the view of damage.

If some people saying that discussed accident didn't produse big enough danger to passenger's (supposed) head and body, then I don't know what to say. Do yo need a train hit to deploy side airbags? Is it for trains only

alphaz

As I said in an earlier post that I would be talking to a Nissan Rep. today.
That was not the case. Nissan sent an INDEPENDENT paint person to look at my Z.
I was informed that :

1) I was not allowed to talk to him.
2) I was not allowed to see the results of his evaluation of my paint job.
3) I may find out in 48 hrs what Nissan plans to do about my paint job, if anything.

I was hoping to talk to a Rep. about the SAB's and HEAD CURTAINS that did not deploy. Wish I could report more.

irishfan

This is exactly what I meant by "nothing I saw". The sensors are basically accelerometers that measure the rate of change of motion in a certain direction. If there is not enough acceleration/deceleration in the measured axis, the airbags will not deploy, as they would cause far more injury than they would protect. This car was not hit with significant direct lateral force to trigger the side air bags. The crumple zones designed into the car appear to have kept the passenger compartment in fairly good shape, particularly considering that the initial collision was obviously of considerable magnitude. The secondary collision which damaged the side was at a lower speed and less dangerous angle and location.

Zephod

Also, the secondary impact is close to the first, so the structure was already weaken from the initial impact. This could result in body damage that is greater then if it was just a side impact. So the side impact may not have been as great as the damage may seem to indicate.

I would also guess that most of the engineering and control logic are designed around a single impact. After the first impact, what the system does on subsequent impacts is undefine or not well define.

Mike821

Umm yeah I think we all understand that much... Deceleration/negative acceleration/G's - all same thing... The basic point that people here seem to not like is the fact that the airbags didn't diploy in a significant collision. It doesn't matter why/how whatever. We know that the door is not made out of carton so the hit must have been significant enough to make such damage. Significant hit is directly proportional to the amount of decelaration, and I know from experience that not much is needed to deploy side airbags in this car

Mike821

Wow that's a really informative post. Shows how much you know.

Acceleration = velocity/time. Do the math. If you don't like it, send an email to Mr. Newton...

Mike821

The stronger the hit, the faster the decelaration is. If you disagree, stop smoking that sh*t

Chebosto

iTrader: (43)

was there a sound of a coconut going "BOK!" ? just kidding

whoa. that must be really painful.

you'd think nissan would implement smart airbags that wouldnt deploy at such a low speed unless the accelerameter senses severe lateral movement...

Mike821

That's what I was saying earlier... I have no idea why the bags popped.

Them Bones

I remember seeing a bumper test on Dateline about a year ago where they were testing cars to see what kind of damage was caused by a 5 MPH hit. Well, they ran a new Volvo into the barrier at 5 MPH and the airbag popped! The NHTSB (sp?) guy was speechless. Needless to say, a redesign was in order after that show aired.

-TB

raceboy

Totally false statement from a physics standpoint. Think of this: The car has the drivers side against a wall. Car is then hit at 20mph by another car on the passenger side at a 90 degree angle. Since the car cannot move in the direction of the wall, there would be almost no acceleration of the vehicle that took the impact, and the bags would not deploy, even if the hit was at a higher speed. I know that is not real world, but it does make the statement false. The car can take a hit that does that type of damage without a lot of lateral acceleration. It also looks to me as if that blow was not at a 90 degree angle to the side of the car. It looks like that hit caused much more forward/backwards axis acceleration than lateral and that would negate the need for airbag deployment.

Vlad

Another good example is hitting car by train the hit is terrible - believe me. And train doesn't deccelerate a bit! Will you Mike821 say it's because train driver also smoke bad ****? Or just train is way too heavy?
So next time, please don't foget the mass in your math.

JeffRich

this photo looks all to similar to what just happened to me. I was t boned on my passenger side by someone going 60+ as I was rolling at maybe 15. No airbags what so ever. Luckily no passenger.

I've talked to a few guys here in AZVQ and many people had accidents wth no bags deployed. This is a major problem.