Rate-Activated Tethers (RATs)

Award Year 

A technology developed to help protect physical injuries to warfighters that first drew attention from the National Football League (NFL) is now poised to emerge as the key to an entire family of innovative wearable protective products. Protecting warfighters’ vulnerable body parts—ankles, heads, joints—has always presented a Catch-22: rigid braces, straps, and other protective gear can help protect soldiers from injury in extreme situations, but they also restrict movement in ways that often (more) make them impractical. But the rate-activated tethers developed by the Army Research Laboratory (ARL) hold the promise of offering both protection and flexibility—for soldiers, athletes, recovering patients in physical therapy, and a variety of other uses. ARL’s rate-activated tethers, or RATs, are basically straps filled with shear thickening fluids—compounds that are “rate responsive,” meaning that they are liquid and flowable when at rest or low speeds, but quickly transition to a solid-like material with the consistency of wet sand when sheared rapidly or stressed. ARL's RATs combine shear thickening fluids with other design components to create a flexible strapping material that exhibits 10-100 times greater resistance and support when strained quickly versus slowly. Initially explored to replace rigid ankle braces for paratroopers, the technology’s potential is now evolving into what could become a full ecosystem of protective wearables both in and beyond the military. The technology first drew external attention in the NFL’s Head Health Challenge initiative, where it was one of only seven grant proposals to improve football players’ head protection that received funding from the league, followed by a second round of follow-on funding. Collaboration with the NFL and the Defense Advanced Research Projects Agency’ s Warrior Web project further refined the project and led to Cooperative Research and Development Agreements and partial licensing agreements with the technology’s first two commercial partners. Presently, a number of companies are exploring using the technology for a broad range of applications under the auspices of a deliberate technology transfer strategy by ARL that envisions agreements with multiple partners to ensure the technology is used to its full potential across a wide line of applications. At this time, the two that have been publicly disclosed and prototyped by partner companies are ankle protection and bands that provide variable tension for use in physical therapy. However, other companies in the process of licensing the technology picture a full range of protective gear for athletic use, with clear dual-purpose potential for future military applications. Combined with one company’s proposal to manufacture the material, these ongoing efforts suggest the strong potential for a broad ecosystem of developers of mainstream commercial products based on ARL’s technology in the near future. Contact: Dr. Eric Wetzel, (410) 306-0851, Winners not pictured: Dr. Richard Dombrowski Dr. Joe Hitt Russ Hubbard Dr. Austin Leach Thomas Mulkern (less)