Paper Number
PO116 

Session
Poster Session

Title
Shear thickening fluid (STF) – nanocomposites for improved hypervelocity impact protection against micrometeoroids and orbital debris

Presentation Date and Time
October 8, 2014 (Wednesday) 6:05

Track / Room
Poster Session / Poster

Authors (Click on name to view author profile)

1. Cwalina, Colin D. (University of Delaware, Department of Chemical and Biomolecular Engineering)
2. Dombrowski, Richard D. (University of Delaware, Department of Chemical and Biomolecular Engineering)
3. Wagner, Norman J. (University of Delaware, Department of Chemical and Biomolecular Engineering)

Author and Affiliation Lines (in printed abstract book)
Colin D. Cwalina, Richard D. Dombrowski, and Norman J. Wagner
Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE

Speaker / Presenter 
Cwalina, Colin D.

Text of Abstract
Concentrated colloidal dispersions exhibit a rich shear rate-dependent rheology that includes shear thickening at higher shear rates as a result of large lubrication stresses between particles. Composites based on such field-responsive materials are finding increasing commercial use in personal protective equipment against ballistic, stab, and needle puncture threats. The demonstrated ability of shear thickening fluid (STF) to improve the puncture and ballistic resistance of engineering textiles suggests their potential application for use in the extra-vehicular activity (EVA) suit worn by astronauts. In low-earth orbit, astronauts and spacecraft are exposed to the perils of micrometeoroids and orbital debris (MMOD). While generally less than a centimeter in size, these MMOD particles can travel tens of thousands of miles per hour, rendering them highly energetic. In a collaborative effort with NASA scientists from the Hypervelocity Impact Testing Facility (HITF) at Johnson Space Center, we have conducted hypervelocity impact (HVI) testing at White Sands Remote Hypervelocity Test Laboratory (RHTL) on a prototype lay-up containing STF-Kevlar® that was lighter in mass than the existing EVA suit. We identified the ballistic limit up to 7 km/s and found the results to be comparable to existing available suit data. An energy balance on the projectile and target provides a rational method to understand the observed HVI performance and motivates the need to better understand the rheology of STFs at ultrahigh deformation rates where inertial effects are important. These EVA suite prototype materials are scheduled to be placed on MISSE-X external test station of the International Space Station in the coming months to investigate the effects of the low-earth orbit environment on their stability and MMOD resistance.