Dynamic mechanical characteristics of starch-based shear thickening fluids at high strain rates

Shear thickening fluids (STFs) exhibit unique rheological properties, but research predominantly focuses on SiO2-based systems for ballistic applications, with limited studies on starch-based STFs (S-STFs) at high strain rates. This study investigates corn, potato, and mung bean S-STFs subjected to dynamic compression (1870 s−1 ∼ 8510 s−1) via split Hopkinson pressure bar (SHPB) testing. Results show that S-STFs exhibit mass fraction and strain rate dependent behaviors regarding peak stress, impact toughness, and transition times. As the starch mass fraction increases from 50 wt% to 60 wt%, the peak stress of corn starch-based STF rises from 96.37 MPa to 126.95 MPa, and impact toughness increases from 77.36 Jm−3·106 to 98.72 Jm−3·106, while the transition time decreases from 57 μs to 26 μs. Similar trends are observed in potato starch-based and mung bean starch-based STFs. Higher strain rates lead to elevated peak stress and improved impact toughness, with reduced transition times. Mung bean starch-based STF exhibits superior shear thickening behavior due to more uniform particle size distribution and higher aspect ratio. A phenomenological model establishes quantitative relationships between particle morphology, mass fraction, and compressive response. This study provides significant insights into the behaviors of S-STFs in extreme environments.