The synergistic effect of temperature and loading rate on the mechanical behavior of shear thickening fluid reinforced with graphene nano-platelets using split Hopkinson pressure bar

Abstract

Fumed silica shear thickening fluids (STFs) have gained significant interest in recent years due to their distinctive rheological behavior and potential applications in various fields. The objective of this study is to build upon previous research by employing the split Hopkinson pressure bar (SHPB) and the squeeze flow theory to investigate the combined effect of the strain rate and the temperature on the mechanical behavior and thickening time evolution of STFs. The study comprises both pure SiO2-STF with varying concentrations and SiO2-STF reinforced with graphene nano-platelets (GNPs). The impact tests were performed at strain rates up to 23,000 s–1 and at a broad temperature range (-50 °C, -25 °C, +0 °C, +25 °C). The results showed that STFs exhibit a strain rate and temperature dependence in peak stress, impact toughness, and fluid-to-solid transition time. At low temperatures, the shear thicknening behavior of the STFs was significantly enhanced, resulting in a reduced thickening period and improved mechanical properties. Additionally, the study showed that the addition of GNPs additives to SiO2-STF enhances the mechanical performance and the dynamic response of the STF at extreme thermal and loading conditions. The GNPs have strengthened the contact coupling force between particle clusters, enabling the fluid to complete a dynamic response within 5 µs with a maximum peak stress of 350 MPa. These findings provide valuable insights into the behavior of these materials under extreme conditions and could be useful for the development of new applications.