Authors: Mohammad Rauf Sheikhi, Assoc. Prof. Selim GÜRGEN

Abstract:  From the crashworthiness of vehicles to the protection of human bodies, energy absorption of materials has become a challenging issue. In this work, multi-layer composites including cork, warp-knitted spacer fabrics (WKSF) and foam were enhanced by shear thickening fluid (STF) for energy absorbing purposes. STF was filled into the foam layers in the STF included composites. To make the study concise, a constant thickness was established for the multi-layer composites and they were subjected to a low-energy impact testing for an energy level of 16.18 J. Direct comparison was established between the structures with and without STF to determine the influence of STF in the energy absorbing performance. According to the results, STF inclusion enhances the energy absorption of the composites. Furthermore, specific energy absorptions, energy absorbing rates per unit mass, are also increased for all configurations. Last, maximum impact forces acting at the back face of the composites are lowered by the addition of STF. As the most effective design in specific energy absorbing, Config-12 consists of a 20 mm coarse-granule cork layer, a foam layer and a WKSF layer from top to bottom. The cork layer at the impacting face distributes the impact energy in the lateral directions while the foam and WKSF layers show whole-body compression instead of local deformation at impact point. For this reason, whole structure contributes to the energy absorbing mechanism including the far-fields from the impact point.

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