The encyclopedia · Engineering & Operations · Product decision · 1952-1959
Mercedes' crumple zone made the car absorb a crash's energy instead of the occupants
Béla Barényi split the body into three boxes so a crash crumpled the ends and left the passenger cell intact.
Mercedes-Benz · Daimler-Benz
the move
The conventional belief was that a safe car must be rigid and not yield. Béla Barényi, who had proposed the idea as early as 1937, argued the opposite: a crash's kinetic energy has to be absorbed through deformation to protect the people inside.
He split the body into three boxes, a soft front section, a rigid passenger cell, and a soft rear section, so the crash energy is consumed by the folding metal and the passenger cell stays strong. German patent DBP 854 157 was granted on 28 August 1952.
Mercedes built the idea into the W111 series from 1959, and the three-box safety body became the template for passenger cars, replacing the old approach of trying to make the whole vehicle stiff enough to ignore a collision.
why it works
- Deforming the ends over a longer distance reduces the peak deceleration felt by occupants.
- Spending the crash energy in the crush zone keeps it from being transferred to the passenger cell.
- A rigid passenger cell keeps the occupant space from being crushed by a relatively minor collision.
- It made safety a structural design feature rather than a matter of heavy armour.
what transfers
When a system has to survive an extreme event, decide what is allowed to fail and engineer it to fail first, protecting the one part that must not.
what came after
The crumple zone was first applied on the Mercedes-Benz W111 models of 1959, and it spread across the industry, where it became a standard element of crash safety along with rigid passenger cells and later softer interior surfaces.
references
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