Low‐Velocity Impact Behavior of GFRP With Shear Thickening Fluid Modified Resin Matrix

ABSTRACT This study aims to investigate the low‐velocity impact (LVI) response of glass fiber reinforced polymer (GFRP) laminates with the addition of shear thickening fluid (STF) in a matrix of thermoset resin. Two different mass fractions of SiO ₂ nanoparticles were incorporated into polyethylene glycol 200 (PEG 200) to prepare two types of STF, and their rheological properties were tested. Then, LVI was carried out on the laminates with various STF‐to‐resin mass ratios fabricated by the vacuum‐assisted resin injection process (VARI). The results show that the incorporation of STF enhances the impact resistance of GFRP laminates, with notable improvements in toughness and interlaminar strength. As the aggregation of nano‐SiO ₂ particles within the STF increases viscosity, the bond enhancement between the matrix and the fibers within the laminates results in less interlaminar delamination in the laminates with STF. Notably, under high‐energy impact, only laminates with elevated mass fractions of SiO ₂ and STF‐to‐resin mass ratios were not penetrated, indicating improved strength. Furthermore, within a 20% range, an increase in the STF‐to‐resin mass ratios leads to greater displacement and lower peak force.