Energy absorption processes in fibrous composites

The objective of this investigation is to determine the contribution of fibers in polymer matrix composites during impact. Experimental measurements were made using specialized specimen designs and test methodologies to isolate the roles of fiber deformation and fracture as well as matrix–fiber interaction. Three types of fibers were examined: Spectra-900 PE, Kevlar-49 and graphite. Experimental results show that PE possesses the highest deformation energy density (normalized to volume), followed by Kevlar and graphite. A similar trend was observed for fracture energy. This trend correlates well with the toughness of these fibers estimated from the strength and ductility of the materials. The energy absorption capacity of the fibers examined was found to increase with increasing strain rates as a result of the generation of stress wave during high velocity impact. Experimental measurements were made to determine the energy absorption characteristics of fabric, fibers and composite structures. Results show that the fiber contribution is significant in the composite structures examined.