Date: Sat, 3 Apr 1999 15:43:54 +0200 From: "kentbassbutler" <stephanlucanopsamail.com> Subject: CHRASH TESTS,CRUMPLE ZONES, WEIGHT
There seems to be a confusion on the effect of weight, height or size in an accident or in crash tests. IMPORTANCE OF THE CRUMPLE ZONE In an accident, the general goal is to keep the safety cell ( where you sit) intact at the highest speed possible without killing the occupants, this imply that the safety cell has to be as stiff as possible ( to avoid the collapse of the safety cell and the intrusion of the wheels , engine or steering wheel --->deadly) and has to be surrounded by a crumple zone that is not too stiff (------> the shock would kill instantly the occupants because of the deceleration ) nor too soft (-----> useless, the car you'd hit would go right thru the crumple zone and you'd be killed anyway). A trade-off has therefore to be found for the strenght of the crumple zone : at low speed( 15mph for example), the car with very soft crumple zone might inflict less damage to the occupants than a car with a stronger crumple zone : the occupants would be shaken badly in the 2nd car and "wouldn't feel anything" in the first car. However, at 40 mph, the occupants of the 1st car would probably be killed by the intrusion of the engine, the steering wheel where in the 2nd car, because of the " extra margin" allowed by the stronger crumple zone, the occupants would probably be wounded but still alive. It is therefore possible to find a car # 1 that manage to protect the occupants better than car # 2 at a speed of 40 mph yet car #2 could be safer than car #1 at a higher speed than 40 mph because car#2 has a stronger crumple zone than car #1, allowing it a " last resort" extra safety margin than would not have car#1. That is why it is crucial to see how well the structure of a car perform in a crash test: even with identical global crash-test ratings at a specific speed, only the one whose structure hasn't started to collapse will allow you that extra safety margin in case of a stronger impact. Note that the size of the crumple zone is important : that is why, IN GENERAL, minivans (with shorter "noses") don't perform as well as cars in frontal crash tests. So crumple zones have to be "attached" to the stiffest cell possible and must be not soft nor too strong! IMPORTANCE OF WEIGHT AND CRASH TEST RESULTS. WEIGHT MATTERS WHEN 2 OR MORE VEHICLE ARE COLLIDING. Crash tests results have nothing to do with the weight of the car tested.It has to do with how well the safety cell-crumple zone-restraint system combo have been designed. So if you drive a very light car with good crash tests results into a wall , you will be better off in that car than in a truck , even 2 times heavier, that would have "bad" crash tests results. However, if that truck hit the small car, eventhough that car has better crash tests results than the truck, you'd be better off in the truck because of the weight difference. In general, you'd be safer in a heavy vehicle, regardless on how it performs in crash tests.
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