By T’Jae Ellis
ARL Public Affairs Office
Technology created by an Army Research Laboratory engineer that’s positioned to help the NFL as well as soldiers in combat reduce head injuries is part of an American Chemical Society video produced to celebrate chemistry in everyday life.
The video was featured last week during the society’s annual conference in San Francisco. It was also shown during the 10-day South by Southwest® Conference & Festival in Austin, Texas last month. The annual event celebrates the convergence of the interactive, film, and music industries by fostering creative and professional growth within “one of the most diverse, collaborative, and inventive communities in the world,” according to the conference website.
Shear-thickening fluids take center stage in the video production. STFs consist of hard particles suspended at high concentration within a liquid, and have the unique property of remaining fluid until subject to a sudden force. ARL’s Dr. Eric D. Wetzel, research area manager for Soldier Materials, began collaborative research on STFs over 15 years ago with University of Delaware Professor Dr. Norman Wagner. Prof. Wagner has also co-founded STF Technologies, a private company in Newark, Del.
As Wagner explains in the video, STFs are “field-responsive” materials so the harder the materials are pushed or the more pressure applied to them, the harder they push back or resist flow.
In 2002, ARL and UD discovered a way to incorporate STF into fabrics like Kevlar, creating a unique new protective material that’s proven resistant to pointed objects such as needles or ice picks. As mentioned in the video, STF-fabrics are also being used to provide enhanced astronaut protection for future manned exploration missions, and to develop puncture-resistant surgical gloves to protect healthcare workers from needle stick injuries and the associated risk of contracting diseases such as hepatitis and HIV.
Wetzel is a co-inventor on a 2016 ARL patent for “rate-activated tethers”, which incorporate STF into an elastic tube to create a stretchable, flexible material with an unusual property: when stretched at low speeds, the strap is elastic like a rubber band, but at higher extension rates it becomes up to 100 times more resistive in a fraction of a second. These speed-triggered materials have a wide range of potential applications from self-adjusting helmet chinstraps to ankle braces that are both supportive and comfortable.
ARL also leads an NFL-sponsored research program to use the straps to couple a helmet to the wearer’s body, allowing for free range of motion under normal conditions and stiffening to protect the head from injury upon impact like a collision.
“We had this idea that if we could get the response of the shear thickening fluid but in something that’s more like a strap that is speed dependent in its response, you could potentially make a wearable device that could reduce the risk of concussions and head injury,” Wetzel explains.
The video also highlights how UD researchers are now studying ARL’s rate-activated tethers to create improved lower leg prosthetics, which could directly improve the lives of disabled Army veterans.
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