Filler shape and volume fraction effect on dynamic compression behaviour of glass filler reinforced epoxy composites

The effect of filler shape and volume fraction on the dynamic compression behaviour of low volume fraction rigid particle filled polymer composites is demonstrated by performing experiments using split-Hopkinson pressure bar (SHPB) setup. The results indicate negligible influence of spherical particles on the mechanical behaviour of composites due to the large inter-particle separation distance at low volume fractions. On the contrary, the mechanical behaviour of composites is considerably affected by milled-fibres due to the large surface area to volume ratio of slender fillers which significantly decreases the inter-particle separation distance. The computational analysis in combination with experimental observations reveals two competing deformation mechanisms, the constraints provided by fillers to the polymeric chain movements and increasing strain softening in the matrix due to magnified stresses in between the particles. Depending upon the filler volume fraction one of the two mechanisms dominates, thus tailoring post-yield stress vs. strain curves of filled polymers.