While it is unlikely that concussions and the risk of head injuries will ever be completely eliminated from football and other contact sports, scientists at the University of California Santa Barbara, the US Army Research Laboratory and HRL Laboratories report that they’ve developed a material that might significantly reduce those risks. The material is composed of elastic microlattice pads, and the researchers believe it can be used to make helmets that dramatically improve the level of protection against concussion and brain injury caused by repeated concussive and sub-concussive head hits. Their research is reported in the November 27 issue of the journal Matter.
Helmets used in sports like football, ice hockey, baseball, softball and lacrosse, as well as in military combat need materials that can protect against repetitive impact. One challenge has been designing materials that can remain effective over time, are affordable to make, have low mass and can be widely distributed. Improvements in helmet foams and pads over the last few decades have been relatively marginal. The researchers believe their new microlattice materials can handle repetitive impact as well as single hits better than even the most state-of-the-art foams currently available.
“Our technology could revolutionize football, batting, bicycle, and motorcycle helmets, making them better at protecting the wearer and much easier to have on your head due to the increased airflow,” says Eric Clough, a researcher at HRL Laboratories, a materials science doctoral student at the University of California, Santa Barbara, and the lead scientist on the study.
With a lattice-like appearance similar to the Eiffel Tower’s wrought-iron design, the photopolymer-based material is strong and sturdy, but still allows air to pass through. This will keep athletes heads cooler than the foam padding in currently-available helmets. The material is also easily adjusted and can be tailored to absorb different types and levels of shock by adjusting its components.
Three different variations of the microlattice material were tested for impact absorption in comparison to other helmet foam. In order to measure the response of the material itself, with no accounting for the the shape of any helmet or other properties, the researchers used a double anvil fixture that simulated impacts like those that would happen when a helmet was struck. Next, the ability of the material to withstand multiple consecutive blows was measured. The material was made into helmet pads and tested according to the test specifications of the US Army Advanced Combat Helmet guidelines.
The new material showed great promise, outperforming the best expanded polystyrene foam currently available by absorbing 27% more of the energy of a single impact It also beat the top vinyl nitrite foam, absorbing energy at a 48% more efficient rate. Perhaps most important, it beat out competing microlattice designs. It not only absorbed 14% more energy from a single hit than the competitive microlattice material, but remained intact to absorb further hits, rather than buckling and becoming ineffective after a single hit.
“A noticeable percentage of improvement in impact absorption was something we were hoping for, but the actual numbers were better than we expected,” says Clough. “Our testing shows that the pads work better than anything on the current market.”
The new microlattice pad has already been licensed through HRL to the sports tech company VICIS. The next round of research will be directed specifically at assessing the material’s use for military headgear. Clough cautions, however, that this material is not a “magic bullet” capable of protecting the user from any and all head injuries.
“Wearers of helmets with our padding can enjoy the benefits but should never assume they are completely protected from injury or look to test the limits of the product by possibly endangering themselves unnecessarily,” he says. “Even a great helmet can’t always protect you from every injury all the time.”
While this material is no absolute guarantee of safety and concussions can happen in a variety of ways in both combat and sport, this certainly seems to be a step forward in improving protective outcomes for the heads – and brains – of athletes and warfighters.
Keep the faith and keep after it!
Journal Reference – Eric C. Clough, Thomas A. Plaisted, Zak C. Eckel, Kenneth Cante, Jacob M. Hundley, Tobias A. Schaedler. Elastomeric Microlattice Impact Attenuators. Matter, 2019