Researchers from North Carolina State University recently found that composite metal foam (CMF) could significantly improve auto safety during frontal collisions.
The team used computational models to run detailed simulations and found that adding CMF to a cars front rails would help absorb more energy during high-velocity impacts.
These foams have hollow spheres made of metals or alloys embedded in a metallic matrix. The material is both lightweight and very strong at absorbing compressive and impact forces. The technology could also be used in aircraft wings to vehicle armor to body armor. You may remember from a few years ago, but CMF was the technology used to stop 50-caliber rounds and turn armor-piercing bullets to dust on impact.
CMF can slow the rate at which a vehicle decelerates during a crash, improving driver and passenger safety. During a crash, the bumper transfers impact energy to the front rails, which are designed to absorb that energy. These front rails are meant to deform in a way that limits the amount of energy that is transferred to people in the vehicle, and to stop the vehicle from decelerating too rapidly. When you stop too fast severe injuries happen.
The industry has a pair of common front rail designs: rectangular cross-section rails, which are long, hollow steel rectangles, and double-octagonal rails that have two long, hollow aluminum octagons stacked on top of one another.
Using publicly-available material and design data for the conventional front rails to conduct detailed computational modeling, the study found that CMF front rails allowed vehicles to withstand much higher impact speeds before things got dangerous.
Compared with double-octagon rails, CMF of the same weight and length reduced the maximum deceleration experienced during a 55 mph crash by about 38%, reduced overall crash severity by about 45%, and reduced the likelihood of serious head injury by about 45%.
Compared with rectangular rails at the same impact speed, CMF of the same weight and length, reduced maximum deceleration by about 84%, crash severity by about 94%, and head-injury potential by 83%.
Combined with CMF’s previously demonstrated resistance to heat and fire, the new findings also point to potential applications in electric vehicles, including structures designed to help protect high-voltage battery packs from crash-induced damage.
Next, the team hopes to work with auto industry stakeholders to conduct testing in existing front rail designs and eventually develop new designs that use CMF to not only improve safety, but fuel efficiency as well.
