Shock wave attenuation using sandwiched structures made up of polymer foams and shear thickening fluid

The present study experimentally investigates the shock wave attenuation performance of various sandwiched structures made up of different polymer foams (expanded polystyrene and polyurethane foam) with and without shear thickening fluid (STF). STF is a non-Newtonian fluid whose viscosity increases with increase in shear rate due to the formation of hydro clusters produced by the increased hydrodynamic forces acting between the interstitial spaces. Two layers of polymer foams have been considered for the shock protective material and the space between the layers is filled with shear thickening fluid. The shock wave is experimentally generated from a shock tube facility and is allowed to impinge on a target plate kept at 10 mm downstream to the shock tube end. It is seen that the protective material with polyurethane foam and shear thickening fluid (polyethylene glycol+silica nanoparticles) reduces the shock overpressure by nearly 35.51 %, whereas the protective material with only polyurethane foam (with the same thickness) reduces the shock overpressure by only 13.17 %. Similarly, the protective material with expanded polystyrene and shear thickening fluid reduces the shock overpressure by nearly 32.16 %, whereas the protective material with only expanded polystyrene (with the same thickness) reduces the shock overpressure by only 10.49 %. Hence, it is evident that the shear thickening fluid between the polymer foam layers greatly helps in shock wave attenuation.