Army researchers and industry partners recently published a study showing how they have developed new materials and manufacturing methods to create more powerful helmet padding that reduces the likelihood of head injuries in combat and recreational helmets.
A team at the Army Research Laboratory of the U.S. Army Combat Capabilities Development Command and its partners at HRL Laboratories used the advances in 3-D printing to create new helmet pads consisting of highly tuned open-cell lattice structures.
“Careful control of the grid pattern gives the padding novel compression properties that reduce peak head acceleration in blunt impact events compared to existing state-of-the-art foam padding,” said Dr. Thomas Plaisted, the laboratory’s project manager. “The tests showed a 27% increase in energy absorption efficiency when fitted into a combat helmet compared to the most powerful foam pads currently available”.
A significant challenge in designing protective padding is to provide the highest level of impact protection while minimizing weight and space inside the helmet, Plaisted said. The padding must be comfortable for a soldier to wear a combat helmet for extended periods of time,” Plaisted said.
“Typical multiple impact cushioning materials include closed-cell expanded polypropylene and vinyl nitrile foams that absorb impact energy by collapsing the internal pores when they are compressed,” he said. “The material is carefully tuned to yield at a threshold force or acceleration specific to the head’s tolerance, thereby mitigating injuries.
Recent advances in additive manufacturing techniques have enabled the production of cellular materials with an architectural lattice topology.
“By designing the cellular architecture, we have demonstrated improved control over the collapse process in elastomeric grids, which enables shock absorption performance that exceeds that of the most advanced foams for both single and multiple impact scenarios,” Plaisted said. “An improvement over the most advanced vinyl nitrile foam helmet pads was achieved during a standard helmet test, resulting in lower head acceleration. This breakthrough could pave the way for helmets with improved injury protection. The open-cell design of the mesh further contributes to comfort and breathability and dissipates heat away from the head”.
Researchers recently briefed their transition partners at the CCDC Soldiers’ Centre on the performance of new padding materials and helmet suspension technologies to mitigate blunt head injuries on impact. The laboratory is transferring this technology to the Center for further evaluation and implementation in future helmet systems.
“Building on this work, the CCDC SC has initiated its own research efforts to develop and evaluate additive-produced helmet padding,” said Plaisted. “At the same time, we have provided updates on an alternative helmet padding technology, the rate-activated tethers, which was invented at ARL and has shown even better performance in reducing blunt impact injuries. We are working with the center to find partners in the helmet industry who can integrate the new rate-activated tethering technology.
The Army’s fundamental responsibility is to equip, train and deploy soldiers with the tools and resources that will enable them to contact and destroy the enemy while providing world-class protection, Army officials said. As a priority in the modernization of the Army, soldier lethality reduces capability gaps to improve a soldier’s ability to fight, win and survive through increased lethality, mobility, protection and situational awareness to facilitate the rapid acquisition of enhanced capabilities.