Effect of silica weight fraction on rheological and quasi-static puncture characteristics of shear thickening fluid-treated Twaron® composite

Intelligent energy shunting fluid/fabric base structure which utilizes well-processed shear thickening fluid has been developed. The shear thickening fluid has been synthesized by a powerful mechanical stirrer to disperse 12nm silica particles into polyethylene glycol 200g/mol at three concentration levels from low to near maximum packing as 15, 25 and 35wt%. Examining the rheological behavior of the shear thickening fluid indicates that the increase of shear thickening fluid concentration leads to significant increase in the suspension's initial, critical and ultimate (up to 10(4)Pa.s) viscosities, reduction of the critical shear rate, increase of viscoelastic modulus and instability of the suspension. The quasi-static puncture test results demonstrate with the increase of shear thickening fluid concentration, the maximum bearable load by the 15, 25 and 35wt% shear thickening fluids-treated Twaron (R) composites increases by 132, 315 and 362%, and the energy absorption increases by 143, 159 and 209%, respectively, compared to the neat fabric. Regarding penetrator structure and dimension, by using rounded penetrators, windowing and pull-out mechanisms would be expected at low velocities. However, sharp-nosed penetrators most likely cause yarns to push aside that is not taken into account as a perfect criteria for investigation of puncture resistance performance. Also, larger penetrators have a larger presented area of impact and, as a result, break more number of yarns to penetrate the fabric.