ENERGY-ABSORPTION PROCESSES IN FIBROUS COMPOSITES

The objective of this investigation is to determine the contribution o f fibers in polymer matrix composites during impact. Experimental meas urements were made using specialized specimen designs and test methodo logies to isolate the roles of fiber deformation and fracture as well as matrix-fiber interaction. Three types of fibers were examined: Spec tra-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 f racture energy. This trend correlates well with the toughness of these fibers estimated from the strength and ductility of the materials. Th e energy absorption capacity of the fibers examined was found to incre ase with increasing strain rates as a result of the generation of stre ss wave during high velocity impact. Experimental measurements were ma de to determine the energy absorption characteristics of fabric, fiber s and composite structures. Results show that the fiber contribution i s significant in the composite structures examined. (C) 1998 Elsevier Science S.A. All rights reserved.