AP Physics Mechanics
Extra Credit Essay
An incredible automobile safety feature that makes accidents more survivable is the crumple zone of a car. Crumple zones absorb a good amount of the kinetic energy associated with the crash, which does not transfer to the occupant. Parts of the crumple zone include the hood, bumpers, bumper shock absorbers, and quarter panels. 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 core problem is that a typical car, weighing more than 4,000 lbs. driving 60 mph has a huge amount of momentum. If a car hits something at that speed, all of the momentum is stopped with a massive amount of force required because change in momentum equals force multiplied by time. All of that force is then transferred to the passenger. Adding in features that will make things crumple, such as plastic bumpers and shock absorbers, will reduce the amount of energy that reaches the passenger, because that energy gets absorbed when those features break upon impact.
According to a British Motor Insurance Repair Research Centre study of where on the vehicle impact damage occurs: 65% were front impacts, 25% rear impacts, 5% left side, and 5% right side. Some racing cars use aluminum or composite/carbon fiber honeycomb to form an attenuator that dissipates crash energy using a much smaller volume and lower weight than road car crumple zones. Crumple zones work by managing crash energy, absorbing it within the outer parts of the vehicle, rather than being directly transmitted to the occupants, while also preventing intrusion into or deformation of the passenger cabin. This better protects car occupants against injury. This is achieved by controlled weakening of sacrificial outer parts of the car, while strengthening and increasing the rigidity of the inner part of the body of...
Cited: 1. November 6, 2003 Paul Dvorak (2003-11-06). "Will the crash zone crumple? FEA tells". Machine Design. Retrieved 2012-07-16.
2. Grabianowski, Ed (2008-08-11). "HowStuffWorks "Design Compromises"". Auto.howstuffworks.com. Retrieved 2012-07-16.
3. "Physics in the Crumple Zone | Plastics Helps Save Lives". Plastics-car.com. Retrieved 2012-07-16.
Please join StudyMode to read the full document