Compressive behaviour of shear-thickening fluid with concentrated polymers at high strain rates

Shear-thickening fluids (STFs) exhibit solid-like behaviour at high strain rates. This study focused on STFs with styrene/acrylate particles at 58% volume fraction. The theoretical density of the STFs was 29% lighter than that of the STFswith 54% volumefraction silica particles. The microstructure and dispersion of the particles weremeasured, together with the rheological behaviour of the STFs. Then, the high-strain-rate compressive responses of the STFs were studied using a split Hopkinson pressure bar (SHPB). Along with the implementation of highspeed photography at 100,000 FPS during testing, the stress-strain relations of the STFs at high strain rates were determined. The results showed that the transition of fully solid-like STFs occurred at the mean strain rate of 668.3 +/- 109.7 s(-1). As well, the modulus of the solid-like STFs was first reported as 303.7 +/- 78.0 MPa, lower than the level reported for bulk styrene/acrylate copolymers. The peak stress and impact toughness of the STFs were also determined and were compared to those of silica-based STFs from a previous experiment. In addition, the dynamic behaviour of the solid-like STFs was modelled by a phenomenological method and was further used to simulate the SHPB process by finite element analysis. (C) 2017 Elsevier Ltd. All rights reserved.