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Re: crumple zones

John Coffin writes:
>
>Most German car manufacturers have changed their strategy for crash
>protection.  The idea of crumple zone absorbing energy during a crash has
>two views.  Previous German car manufacturers had soft crumple zone so the
>car would absorb the energy on the collision.  Further investigation
>discovered that in a high speed crash (>40 mph) the crumple zone becomes a
>projectile into the passenger cell since the energy from the crash exceeded
>the energy absorption limit of the crumple zone.  So if the crumple zone is
>strengthen then minor injuries increase in low speed accidents but
>fatalities decrease in high speed accidents.  Fatalities are prioritized
>over minor injuries.  In large part U.S. car manufacturers are still using
>the soft crumple zone idea.
>

I believe it has gotten even more complicated than that.  For a while,
the car makers tried to strengthen the crumble zone as much a possible
until one fine day someone crash tested a Mercedes against a VW Golf
(if I remember correctly.)  The outcome was that the Mercedes was
*too* stiff and caused the Golf to take the bulk of the deformation -
endangering its driver.

Since then, the car makers have sought the happy medium between too
stiff and too soft.  The latest crashes test are into an offset
honeycomb barrier that deforms in a way that is supposed to mimic the
other car.

- -John
'96 318is

- -- 
John Firestone, Alfred Wegener Institut   [email protected]
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