Who

Football players and other athletes, motorcycle riders, soldiers, and anyone wearing protective helmets made with the new microlattice pads will have greater protection from both single hits and a series of impacts.

What

Helmets used in combat as well as football and other sports require impact-absorbing materials that protect against ongoing impacts but it is difficult to design materials that remain effective over time without compromising on volume, mass, or cost. Although helmet foams have evolved in the past decades, improvements have been relatively marginal. The new photopolymer-based elastomeric microlattice material is sturdy but allows air to pass through, a property that would keep athletes’ heads cooler than existing helmets. The material is manufactured by a process called light casting by which a UV light is cast through a patterned template onto a tray of specially formulated liquid resin. The areas of resin exposed to the light will cure and quickly grow into solid polymer struts that then grow together to form the lattice pad. The formulation of the liquid resin can be adjusted to make microlattice that is stiffer, softer, or more compliant, as desired. The material absorbs nearly 14% more energy from a single hit than other microlattices and stays intact to absorb the next round of impacts instead of irreversibly buckling after one hit.

Closeup of a VICIS helmet showing flexibility of microlattice pads pressed into the face guard. (© 2019 HRL Laboratories)

Where

University of California, Santa Barbara; U.S. Army Research Laboratory, Adelphi, MD; and HRL Laboratories LLC, Malibu, CA

Why

The material may pave the way for helmets that better protect football players and other athletes from brain injuries caused by repeated head hits. It also could replace currently used foams in applications such as protective packaging, shock isolators for electronics, and vehicle interiors.

When

Sports technology company VICIS has licensed the microlattice pad technology through HRL. They intend to further develop microlattice impact attenuators and commercialize them in new products to minimize sports-related head injuries. HRL plans to research the material's use in military head protection.

Tech Briefs Magazine

This article first appeared in the February, 2020 issue of Tech Briefs Magazine.

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