Researchers at the University of Wisconsin–Madison have created a lightweight, ultra-shock-absorbing foam that could be used to greatly improve protective headgear.
The new material is an architected, vertically aligned carbon nanotube foam which has unique structural features across multiple length scales. Multiple studies proved that cylinders with a thickness of 10 micrometers or less, when arranged closely to each other, produced a foam with the best shock-absorbing properties.
“I expected the overall properties to improve due to our interactive architecture, but I was surprised by how dramatically the properties were enhanced when the cylinders were 10 micrometers thick,” Ramathasan Thevamaran, professor of engineering physics at UW–Madison, who led the research said. “It was due to an unusual size effect that emerged in the process-structure-property relations. The effect was very pronounced, and it turned out to be quite advantageous for the properties we were targeting.”
Helmet materials that are better at absorbing and dissipating the kinetic energy from impacts before it reaches the brain could help lessen – or even prevent – concussions and other traumatic brain injuries. The new material exhibits 18 times higher specific energy absorption than the foam currently used in U.S. military combat helmet liners. It also has much greater strength and stiffness, which could allow it to provide even more impact protection. Additionally, the new material can remain robustly shock-absorbing at both very high and very low temperatures due to its composition, making it useful for applications in a wide range of extreme environments.
Helmet manufacturer Team Wendy is experimenting with the new material in a helmet liner prototype in order to test its performance in real-world scenarios.
“This new material holds tremendous potential for energy absorption and thus impact mitigation, which in turn should significantly lower the likelihood of brain injury,” Thevamaran said.