Steel bonding agent reduces impact forces of helmet-to-helmet hits
September 3, 2013
One of the most feared football-related injuries is concussion. With the new NFL and NCAA college seasons just about to kick off, fans will be praying that none of their team suffers any serious impact collisions that could end their season or result in memory loss or depression later in life. University of California, Los Angeles (UCLA) biomechanical engineering professor, Vijay Gupta, is testing a special polymer material that when applied to the inside of helmets, can reduce G-force impact by 25 percent.
The special polymer in question started out as a steel bonding agent designed by the professor for US Navy ships eight years ago. It soon became apparent that the joints forged with this material could withstand the impact forces from explosions. Realizing its potential, Gupta and his team at UCLA have started testing 2 mm-thick wafer size strips of the polymer on the inside of football helmets to reinforce the foam padding.
Professor Gupta describes the human head, a three pound brain encased in the hard shell of a skull surrounded by cerebral spinal fluid, as “the best shock-absorbing system you could ever design.” What it was not designed to do, however, is absorb the forces of a helmet-to-helmet collision with a 350 lb defensive tackle capable of covering 40 yards in under five seconds.
The laws of physics tell us that the force of a hit is affected by three factors: body weight, momentum and how quickly the players stop moving. Footballers seem to be getting bigger and faster these days, which is only going to increase the potential for serious injuries during a game.
In response, the UCLA team are experimenting with different formulations of the polymer, altering its rigidity and viscoelasticity, varying its thickness and the placement of the polymer strips inside the helmet. The data from tests utilizing lasers and hammering machines, shows a 25 percent reduction in the force a person would feel from a helmet to helmet clash with the polymer applied. This translates into a similar decrease in the chance of a player suffering a concussion.
“This is a remarkable reduction given that we are adding such a small amount of material that essentially leaves the current helmet unaltered," Gupta said. “If the helmet is altered too much, the concern is that it might affect how players are forced to play and they might not want to wear it.”
Surprisingly, the reduction of G-forces only happens when the polymer is placed inside the helmet on the foam padding. When they applied the special material on the exterior of the helmet the impact forces were increased not reduced.
Sports shoe tests are also being carried out with 1.5 mm-thick inner soles (thinner than existing impact gel soles) made from the polymer. Results show significant advantages in reducing the knee cartilage stresses experienced by regular runners.
Aside from the sporting world, professor Gupta’s polymer could also find lifesaving applications on the battlefield in protecting combatants from the lethal forces of explosions.