Difference between revisions of "Crumple zone"

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[[Image:Mercedes-Benz 220b (1963).jpg|thumb|right|200px|Mercedes-Benz ''"Fintail"'', an early example of a car with crumple zones]]
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[[Image:Mercedes-Benz 220b (1963).jpg|thumb|right|Mercedes-Benz ''"Fintail"'', an early example of a car with crumple zones]]
[[Image:Verkehrsunfall1.jpg|thumb|right|200px|The crumple zone on the front of these cars absorbed the impact of a head-on collision]]
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[[Image:Verkehrsunfall1.jpg|thumb|right|The crumple zone on the front of these cars absorbed the impact of a head-on collision]]
[[Image:Caraccidentinpleasanton(CROPPED).jpg|thumb|right|200px|Activated rear crumple zone]]
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[[Image:Caraccidentinpleasanton(CROPPED).jpg|thumb|right|Activated rear crumple zone]]
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[[Image:Vehicle crash test at the General Motors Vehicle Safety and crash Worthiness Laboratory.jpg|thumb|right|A [[crash test]] illustrates how a crumple zone absorbs energy from a crash.]]
  
The '''crumple zone''' of an [[automobile]] is a structural feature designed to compress during an [[accident]] to absorb [[energy]] from an impact. Typically, crumple zones are located in the front part of the vehicle, in order to absorb the impact of a head-on collision, though they may be found on other parts of the vehicle as well. The crumple zone concept was pioneered by Mercedes-Benz and first introduced on the 1953 180 "Ponton" sedan.  
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The '''crumple zone''' of a vehicle such as an [[automobile]] is a structural feature designed to compress during an [[accident]] to absorb [[energy]] from an impact. Typically, crumple zones are located in the front part of the vehicle, in order to absorb the impact of a [[head-on collision]], though they may be found on other parts of the vehicle as well.  
  
Crumple zones work by lengthening the time a vehicle takes to come to a stop. This reduces the magnitude of the forces and deceleration felt by the occupants, since they are spread over a longer time. Therefore, a properly restrained passenger will have a smaller force applied to their bones and organs, and are more likely to survive a crash.
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An early example of the crumple zone concept was used by the [[Mercedes-Benz]] engineer [[Béla Barényi]] on the 1959 [[Mercedes-Benz Heckflosse|Mercedes-Benz ''"Fintail"'']].
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== Function ==
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Crumple zones work by managing the crash energy so that it is absorbed within the frontal section of the vehicle (energy is transformed by the deformation instead of being directly transmitted through the body of the occupants), while also preventing intrusion into or deformation of the passenger cabin. This acts to ensure that car occupants are better protected against injury. In simplistic terms, this is achieved by controlled weakening of outer parts of the car while strengthening the inner (passenger cabin) part of the body by using more reinforcing beams and increasingly, higher strength steels.
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In an abstract physical sense, a secondary point of crumple zones is to slow down the collision, not just to absorb energy.  The difference between slamming someone into a wall headfirst (breaking their skull) and shoulder-first (bruising their flesh slightly) is that the arm, being softer, has tens of times longer to slow its speed, yielding a little at a time, than the hard skull, which isn't in contact with the wall until it has to deal with extremely high pressures. This effect helps to ensure that restraints hold and don't bruise (keeping the pressure at low levels), or that there is less speed differential between the passenger's body and their vehicle (so one doesn't fly through the windshield).  In short: A passenger whose body indrectly impacts the soft crumple of metal foil that a crash turns a crumple zone into over a few seconds, survives much more often than a passenger whose body indirectly impacts a hard, undamaged metal carbody which has come to a halt nearly instantaneously.
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A common misconception about crumple zones is that they reduce safety by allowing the vehicle's body to collapse, crushing the occupants. In fact, crumple zones are located in front and behind of the main body of the car, compacting within the space of the engine compartment or boot. The marked improvement over the past two decades in high speed crash test results and real-life accidents also belies any such fears. Modern vehicles using what are commonly termed 'crumple zones' provide, on average, far superior protection for their occupants in severe tests than older models.
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The only other general downside to crumple zones is that repair costs are higher in "fender bender" accidents.
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The 2004 [[Pininfarina]] ''Nido'' [[Experimental Safety Vehicle]] locates crumple zones ''inside'' the Survival Cell. Those interior crumple zones decelerate a sled-mounted survival cell.
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== See also ==
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* [[Automobile safety]]
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* [[Crash test]]
  
Their main disadvantage is that they dramatically increase the cost of post-collision repairs for low-speed accidents, where their benefit is already questionable (assuming the occupants are properly restrained). It is not unusual for older cars to be written off even with relatively minor damage due to repair costs exceeding the value of the car.
 
  
 
== External links ==
 
== External links ==
 
 
*[http://members.aol.com/cerick5563/physics/crumple.html Crumple Zones in Automobiles]
 
*[http://members.aol.com/cerick5563/physics/crumple.html Crumple Zones in Automobiles]
 
*[http://www.visionengineer.com/mech/crumple_zones.shtml Crumple Zones(How Do Crumple Zones Work)]
 
*[http://www.visionengineer.com/mech/crumple_zones.shtml Crumple Zones(How Do Crumple Zones Work)]
  
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{{Automobile configurations}}
  
 
[[Category:Automotive safety technologies]]
 
[[Category:Automotive safety technologies]]

Latest revision as of 11:28, 23 January 2009

Mercedes-Benz "Fintail", an early example of a car with crumple zones
The crumple zone on the front of these cars absorbed the impact of a head-on collision
Activated rear crumple zone
A crash test illustrates how a crumple zone absorbs energy from a crash.

The crumple zone of a vehicle such as an automobile is a structural feature designed to compress during an accident to absorb energy from an impact. Typically, crumple zones are located in the front part of the vehicle, in order to absorb the impact of a head-on collision, though they may be found on other parts of the vehicle as well.

An early example of the crumple zone concept was used by the Mercedes-Benz engineer Béla Barényi on the 1959 Mercedes-Benz "Fintail".


Function

Crumple zones work by managing the crash energy so that it is absorbed within the frontal section of the vehicle (energy is transformed by the deformation instead of being directly transmitted through the body of the occupants), while also preventing intrusion into or deformation of the passenger cabin. This acts to ensure that car occupants are better protected against injury. In simplistic terms, this is achieved by controlled weakening of outer parts of the car while strengthening the inner (passenger cabin) part of the body by using more reinforcing beams and increasingly, higher strength steels.

In an abstract physical sense, a secondary point of crumple zones is to slow down the collision, not just to absorb energy. The difference between slamming someone into a wall headfirst (breaking their skull) and shoulder-first (bruising their flesh slightly) is that the arm, being softer, has tens of times longer to slow its speed, yielding a little at a time, than the hard skull, which isn't in contact with the wall until it has to deal with extremely high pressures. This effect helps to ensure that restraints hold and don't bruise (keeping the pressure at low levels), or that there is less speed differential between the passenger's body and their vehicle (so one doesn't fly through the windshield). In short: A passenger whose body indrectly impacts the soft crumple of metal foil that a crash turns a crumple zone into over a few seconds, survives much more often than a passenger whose body indirectly impacts a hard, undamaged metal carbody which has come to a halt nearly instantaneously.

A common misconception about crumple zones is that they reduce safety by allowing the vehicle's body to collapse, crushing the occupants. In fact, crumple zones are located in front and behind of the main body of the car, compacting within the space of the engine compartment or boot. The marked improvement over the past two decades in high speed crash test results and real-life accidents also belies any such fears. Modern vehicles using what are commonly termed 'crumple zones' provide, on average, far superior protection for their occupants in severe tests than older models.

The only other general downside to crumple zones is that repair costs are higher in "fender bender" accidents.

The 2004 Pininfarina Nido Experimental Safety Vehicle locates crumple zones inside the Survival Cell. Those interior crumple zones decelerate a sled-mounted survival cell.


See also


External links