Citation

Atas C, Liu D. Int. J. Impact Eng. 2008; 35(2): 80-97.

Copyright

(Copyright © 2008, Elsevier Publishing)

DOI

10.1016/j.ijimpeng.2006.12.004

PMID

unavailable

Abstract

Owing to their high capability of energy absorption per unit mass, fiber-reinforced polymer-matrix composite materials have been used for automotive crash tubes and armor designs. Laminated composite materials based on stacking up unidirectional composite layers, however, are susceptible to transverse impact loading. This is because unidirectional laminas with different fiber orientations between them can become separated, i.e. delaminated, from high interlaminar stresses due to different properties between them. Once delaminated, the fibers in individual unidirectional laminas can be easily displaced by incoming impactor, resulting in disintegration of the laminated composite materials. The poor impact resistance of laminated composites has hindered their applications in many engineering structures. This paper presents experimental investigations on impact response of woven composites with various weaving angles between interlacing yarns. A method for preparing novel woven composites with small weaving angles is presented. The effects of the weaving angle on the impact characteristics such as peak force, contact duration, maximum deflection and absorbed energy are also examined. An energy profiling method seems to be useful for identifying the penetration and perforation thresholds of the woven composites. The damage process of individual woven composites can be reconstructed from comparing the corresponding load-deflection curves, energy profile and images of damaged specimens. The study concludes that the energy absorption capability and perforation threshold of woven composites can be significantly improved by using a small weaving angle between interlacing yarns. For example, the perforation threshold of [0/20]4 woven composite, which has a weaving angle of 20° between interlacing yarns, is about 40% higher than that of [0/90]4 woven composite, which has a weaving angle of 90° between interlacing yarns. The higher energy absorption capability of [0/20]4 over [0/90]4 is attributed to a lower stiffness caused by a more polarized fiber orientation and a smaller fiber crimp, resulting in a larger maximum deflection, a more extended damage zone and a larger amount of fiber pullout.