The whole point of crash crumple zones is to decelerate the body(s) inside
the passenger compartment to the point that they will survive. Above
a certain point in speed/energy...they will die or maimed severely no matter
Seat belts hold the body but there is a sudden impact when the slack is
taken up. The Air bags then decelerate the head further
All the while the sheetmetal is folding up like an accordion. Anyone
ever see the crumpled sheetmetal ? Here is what a typical frame rail
folded up along the designed in stress raisers
Similar for a monocoque/unibody, but no frame per say...just the front
engine stub rails and body sheetmetal will fold up like this (inside
the outer sheetmetal...fender/etc)
Notice that if the other vehicle's bumper is either above or beneath
this ones bumper...that it will potentially slide over/under this
area
Here is a monocoque/unibody and it's crumple zone
Ratsf..link doesn't work, so here is the direct address:
http://upload.wikimedia.org/wikipedia/commons/6/6c/Lotus_Evora_front_crash_test.jpgAgain, notice that the bumper height important for the stress raisers
to do their job
On that, notice in this picture of how they test...that they do NOT
have a bumper to bumper impact, but to a wall.
another rats...here is the link:
http://upload.wikimedia.org/wikipedia/commons/4/4a/FAE_visualization.jpgThat is how the article's rating is based on...hitting corner of a wall
NOT bumper to bumper. Their side impact is more real world, as they
do have a sled smack (T-Bone) it from the side...but the sled's bumper
height also very important
As for which is better...smaller or bigger...depends on lots of factors
First that the kinetic energy is dependent on both the mass and speed
of each vehicle
As they both crumple...they are consuming kinetic energy. The rates
of consumption dependent on how they are crumpling...or not
Once their crumple distance is consumed to now have the solid portion
of their passenger compartment become involved...the one with more
kinetic energy will impart that onto the event.
That will have the one with less kinetic energy lose ground and move
backwards...meaning the people in the one moving backwards will then
have that kinetic energy imparted on their bodies via: seat belt, air
bag and anything else that strikes them
Much more going on, but that is the basics of it all...
