Shear Thickening Fluids (STF) - Enhanced Textiles for Impact Energy Dissipation, Year 1

Status: Completed

Start Date: 2017-10-01

End Date: 2018-09-30

Description:

The rheological behavior of some liquids can lead to the creation of materials with very unique properties. Shear thickening fluids (STFs), also known as dilatants, are non-Newtonian fluids that stress and shear rates, unlike ordinary liquids where the viscosity decreases with increasing shear rate. One well-known example of an STF is the cornstarch and water experiment, in which the solid-liquid mixture readily flows under low shear; however, when the same mixture is rapidly stirred or struck, it hardens almost instantaneously, resembling a solid. Modern STFs are made from ceramic nanoparticles that are heavily loaded in a carrier liquid. When the shear rate is increased, hydroclusters will form because of collisions with other neighboring nanoparticles and produce a rapid rise in viscosity. The nanoparticles will even lock together and harden when rapidly struck if the shear rate is high enough. When the stress is removed or if the shear rate decreases, the material returns back to its original fluid-like state. In the past decade, STFs made from silica nanoparticles loaded in carrier fluids, such as polyethylene glycol, and impregnated in a fabric have gained attention by the military and law enforcement to have potential for use in liquid body armor [1] and bulletproof vests. More recent interest in STFs include investigating the use of these materials as a layer in spacesuits to provide protection against micrometeoroid orbital debris (MMOD) [2]. Application of STFs impregnated in fabrics for spacesuits could make these materials a promising candidate as a multi-functional deep-space or lunar habitat shell for MMOD protection. The goal is to determine if Shear Thickening Fluids (STFs) embedded in textiles can be used for a lightweight habitat shell to provide effective protection against micrometeoroid orbital debris (MMOD) in a deep-space environment.

Benefits:

There is an agency need for aerospace materials and structures to be more multifunctional to minimize mass and increase payload and mission capabilities. Multiple technology roadmap areas have identified a need for more advanced textiles as a way to integrate multi-functionality into structures. As of now, multiple layers of fabric with a metallic foil are used in soft shell habitat prototypes as an effort to reduce penetration from MMOD strikes. By integrating additional functionality into fabrics, we hope to develop a material that has reliable impact performance with a lower mass than the state-of-the-art habitat shells. If sufficient impact protection under sub-ambient temperatures, low atmospheric pressure, and radiation can be achieved, then mass savings and lower storage volume due to fewer layers of fabric are just a few benefits of integrating STF-enhanced fabrics into a habitat shell.

Lead Organization: Glenn Research Center