Mechanical response of shear thickening fluid filled composite subjected to different strain rates

Shear thickening fluid (STF) has been used in many areas due to its unique rheological property. In this study, the dynamic mechanical properties of STF-filled composite structures were investigated by in-house fabricated drop weight testing apparatuses. Results indicated that the strength and modulus increase with strain rate for all tube structures. Liquid-filled tubes possess similar strength and modulus, which are larger than air-filled tube at all strain rates. However, STF-filled tube absorbs 5 and 4 times more impact energy than air- and silicone oil-filled tubes, respectively. The energy absorption capacity of STF-filled tube increases with input impact energy. Meanwhile, the shear thickening effect of STF is more sensitive to the loading rate than the input energy, which is an important reference for the designing of STF integrated composite. The STF-filled silicone gel achieves repeatable test due to good protection of the encapsulation, which absorbs 4 times more energy than neat silicone gel during impact. Longitudinal symmetrical profile can be achieved for silicone gel encapsulated STF during impact due to the hardening of the STF which leads to a quick balance state. Moreover, the mechanical response of STF is found to correspond with the rheological performance of the STF.