Deceleration Behavior of Shear-Thickening Fluid Impregnated Foams Under Low-Velocity Impact

Sudden acceleration or deceleration can lead to significant damage in sensitive systems such as electronic units, robotic structures and unmanned aerial vehicles. These engineering devices, as well as passengers and drivers, suffer from them in traffic accidents. To protect humans and sensitive devices, several materials and structures have been developed in recent years. Foam-based structures are one of the promising systems for enhanced protection due to their light weight and soft texture. However, foams may have insufficient strength to withstand the loadings during sudden acceleration or deceleration. To compensate for this drawback, a smart material, i.e., shear-thickening fluid (STF) was integrated into polyurethane (PU) foams to gain enhanced protective performance in this study. STF is made up of non-Newtonian materials that have an increasing viscosity under loading. Due to the thickening behavior, STF has been adapted to different types of protective systems. In addition to the conventional STF concept, also known as single-phase STF, the STF was reinforced with carbon nanotube (CNT) fillers to form multi-phase STF. After impregnating the polyurethane foams with single-phase and multi-phase STFs, these structures were subjected to drop tests. In this testing, an accelerometer was attached to the dropping mass to obtain the deceleration curves during the impact process. According to the results, STF application led to a significant reduction in the peak deceleration of the dropping mass. Moreover, CNT fillers in STF provide a further performance gain in terms of protection.