Injuries during work and play, for both civilians and military personnel, result in lost time, decreased productivity, increased health care costs, and reduced quality of life. A common theme in many of these injuries, from sprained ankles to brain injury, is an association between rapid dynamic mechanical input and injury likelihood. Existing wearable protective devices, including ankle and knee braces, helmets, and body pads, are typically constructed from materials whose low-speed and high-speed behaviors are very similar. In contrast, a dynamically responsive material that transforms into a more protective state during high rate mechanical impulses could improve the comfort and performance of wearable protection. The U.S. Army Research Laboratory has invented a dynamic strapping material called a "rate-activated tether" (RAT). RATs exhibit elastic compliance at low speeds, similar to elastic straps, but resist extension with up to 100X more force when elongated at high speeds. The rate sensitivity of RATs is derived from an enclosed shear thickening fluid (STF), a colloidal material with speed-sensitive resistance to flow. This talk will describe the basic design and behavior RATs, the influence of STF and component properties, and challenges with integration. A number of application examples will be presented, including goggle straps, ankle braces, and helmet suspensions. In addition, the unique challenges and opportunities associated with technology development and transition at a DoD laboratory will also be discussed.


3-1-2: Advanced Materials: Design, Processing, Characterization and Applications Plenary Session II

Division / Sponsors: 
Aerospace, Bioengineering, Applied Mechanics, Design Engineering Division, Advanced Energy Systems, Manufacturing Engineering Division, Noise Control and Acoustics, Nondestructive Evaluation, Diagnosis, and Prognosis (NDPD), Nuclear Engineering Division, Process Industries Division, Fluids Engineering, Heat Transfer, Materials, Microelectromechanical Systems, Safety Engineering and Risk Analysis, Computers & Information in Engineering


Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2020/volume/84478

IMECE2020 - Virtual Conference

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