Investigation of high‐strain rate behavior of <scp>shear thickening fluid</scp> encapsulated electrospun <scp>ultra‐high molecular weight polyethylene</scp>/<scp>high‐density polyethylene</scp> fiber composites by split‐Hopkinson pressure bar

Abstract This study examines the high‐strain rate behavior of shear thickening fluid (STF)‐encapsulated samples of an electrospun mat. It comprises sandwich layers of STF‐impregnated ultra‐high molecular weight polyethylene (UHMWPE)/high‐density polyethylene (HDPE) mat enclosed within high‐temperature stretched electrospun neat UHMWPE fabric. The UHMWPE/HDPE mat was chosen for STF impregnation due to its porosity and the texture of its fiber surface, which contains pores, pits, wrinkles, and grooves ranging in size from nano‐ to micron‐scale. This feature enhances the adhesion and absorption of STF into the fiber structure and onto the fiber surface. These STF‐contained and corresponding neat samples were tested using an in‐house‐designed split‐Hopkinson pressure bar. The deformation and fracture behavior of samples were also monitored simultaneously using a high‐speed camera. The results showed that at a higher strain rate, the peak stress and energy absorption of STF‐encapsulated samples were more elevated due to increased inter‐fiber friction, unlike neat samples, which show a declining trend in peak stress and energy absorption due to yarn slippage. Moreover, the deformation during impact in neat samples was higher than in the STF‐encapsulated samples. Highlights Electrospun ultra‐high molecular weight polyethylene and its HDPE blended fibers Interconnected pores and pits facilitated shear thickening fluid (STF) impregnation. STF‐encapsulation improved peak stress and toughness at high‐strain rates.