Rate-activated strapping for improved retention of protective eyewear during impact

Abstract

During impact, protective eyewear can be dislodged and leave the eyes and face vulnerable to injury from secondary impacts. In this study, a rate-activated eyewear retention system is studied and compared to a conventional elastic retention system. The rate-activated behavior of the retention system is due to an enclosed shear-thickening fluid, a high solids-loading colloid that undergoes a rapid increase in viscosity above a critical shearing rate. Tensile testing shows that the force required to elongate this retention system is over 10 times higher when stretched at 100 mm/s, compared to 1 mm/s. A women’s lacrosse goggle mounted to an anthropomorphic test dummy head is used as a model system to compare retention system response. Goggles are impacted by an NOCSAE-certified lacrosse ball at 27 m/s, with a trajectory oriented 45° relative to the anterior side of the midsagittal plane of the head, per ASTM F3077. High-speed video analysis shows that the rate-activated system provides improved retention relative to the conventional goggle strap, with an average of 12 mm of dynamic goggle deflection compared to 65 mm for the conventional design. These results suggest that a rate-activated retention system could reduce injuries by ensuring that personal protective equipment remains in place during impact events.