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Rate Actuated Tether (RAT) Dynamic Strapping Material

The US Army seeks a partner to license and commercialize an innovative self-adjusting "RAT Strap" technology that is stretchable under normal use but rigid in response to large forces

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The US Army has developed a dynamic ligament (a), using simple components (b) and shear thickening fluid, that is flexible and self-adjusting under normal use but highly resistive to rapid movements. Applications include buckle-free helmet straps (c).
The Technology: 

The US Army Research Laboratory (ARL) has developed and tested a patent pending technology that incorporates shear thickening fluid into a dynamic strapping material, called RAT Strap.  The RAT Strap stretches and retracts under normal use in a manner similar to an elastic strap; however, when subjected to a large force, it becomes up to 10x more resistive in a fraction of a second.  The result is a strap component that self-adjusts in size to the user or application, stretches to allow comfortable movement during typical use, but hardens to provide restraint against impacts or other undesirably large rapid movements.

ARL’s technology is simple, consisting of one or more filaments inside a tube filled with a customizable discontinuous shear thickening fluid.  The dynamic ligament could be applied to numerous products, including self-adjusting helmet straps that do not require buckles or adjustment slides, braces that dynamically protect the user under certain potentially injurious conditions, and industrial and military safety gear that is comfortable to wear during typical use but provides enhanced safety and security under adverse conditions.

  • Comfortable & Self-Adjusting:  Like elastic, the RAT Strap will accommodate a full range of desired motion under normal conditions and contract to its original length or diameter until it form fits to the current user or use profile; unlike elastic, the straps behave like a rigid strap under high forces to prevent unwanted dynamic motion.
  • Broadly Applicable:  The RAT Strap could be used in a variety of applications, including sporting goods, safety gear, adaptive braces and prosthetics, and a range of military protective equipment.
  • Simple & Cost-Effective:  Design components are few and simple; shear thickening fluids are inexpensive.
The Opportunity: 
  • Pending US patent application 13/927,985 (published as 2014/0015176) is available for license
  • Potential for collaboration with US Army Research Laboratory researchers