Helmets could soon offer better protection while also being more comfortable, thanks to a new padding material developed by California's HRL Laboratories. It's claimed to be better than foam at withstanding impacts, while also keeping heads cooler and drier.
Created in partnership with the University of California-Santa Barbara and the US Army Research Laboratory, the "elastic microlattice" polymer material has an open internal structure not unlike the interlinked struts of the Eiffel Tower. It is claimed that this feature not only allows the material to very effectively (and repeatedly) absorb impact energy, but to additionally allow heat and moisture to pass through. By contrast, traditional foam padding simply holds sweat against the wearer's head.
In recent tests conducted on "impact attenuator pads" made of various versions of the material, it was found to absorb up to 27 percent more energy from a single impact than the currently best-performing expanded polystyrene foam. During repeated impacts, it absorbed up to 48 percent more energy than the top-rated vinyl nitrile foam.
Additionally, when compared to other microlattice-type materials, it absorbed almost 14 percent more energy from a single hit. What's more, unlike those others, it stayed intact and functional after that impact, as opposed to irreversibly buckling.
The HRL material is manufactured via a process known as "light casting," in which a liquid resin solidifies into a polymer when exposed to a pattern of ultraviolet light. By tweaking the formulation of that resin, it's possible to create different versions of the material that are optimized for stiffness, softness or compliance. This adjustability could allow the padding to find use not only in helmets, but also in applications such as protective packaging, shock isolators for electronics, and vehicle interiors.
Sports tech company VICIS has licensed the technology, and plans to commercialize it. A paper on the recent assessment of the material was published this week in the journal Matter.
Sources: HRL Laboratories, Cell Press via EurekAlert