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Collisionology™

Understanding the Dynamics of a Car Crash

Posted by Chief Automotive on Oct 23, 2015 11:03:44 AM

explorerToday’s vehicles are safer than they’ve ever been. Thanks to safety advocacy groups and higher standards, the cars and trucks on the market today do a much better job of protecting passengers than those made 20 or 30 years ago. Understanding the structural changes that have made that possible, along with the physics of a car crash, will help you have a better understanding of collision repair.

 First, the Physics

Objects in motion have momentum (mass x velocity in case you don’t remember that bit of info from high school), and they’ll stay in motion unless something acts on them (that’s inertia). Something that changes an object’s momentum is called an impulse (force x time).

 As explained in the IIHS (Insurance Institute for Highway Safety) video “Understanding Car Crashes: It’s Basic Physics,” this concept is relevant to collisions because of the time factor. If you slam on your brakes, you’ll stop in a short period of time and feel a lot of force. But if you brake slowly over a longer time, you’ll feel less force. During a crash, when you stop quickly, you experience a lot of force. If your hood were made of rigid material, you’d stop very quickly, putting more force on you, the passenger. But if the front of your car were designed to crumple, it would lengthen the time of the impulse, cutting the force on you proportionally.

 The goal in modern vehicles is for those crush zones to collapse while allowing the passenger compartment to remain intact. From a design standpoint, less rigid materials are used in these crush areas, while things like HSS (high-strength steel) are used in the area housing the driver and passengers.

 The Repair Repercussions

As vehicle designs have changed for the safer, repair methods must change right along with them. For instance, because energy is transferred around the passenger compartment, there could be damage to areas you wouldn’t expect. It’s important to keep up to date with your collision repair training to understand how to check for that damage with computerized measuring and how to correct it.

 You’ll also need to stay in the know about the materials used in today’s car designs. Today’s technicians need to understand how to repair or replace the newest steel, aluminum or boron elements of a car. It’s a matter of learning how to work with these materials and return the vehicle to OEM standards, and that’s why it’s so important for you and your technicians to have regular training and refreshers.

 When you do, the vehicle will be ready for the road, and it will be up to the task of protecting its passengers once again. 

For more on the latest advances in vehicle manufacturing, download our free Structural Design Technology guide.

Structural Design