THE EFFECT OF WEAVE PATTERN AND CRACK-PROPAGATION DIRECTION ON MODE-IDELAMINATION RESISTANCE OF WOVEN GLASS AND CARBON COMPOSITES

The effect of weave structure on the interlaminar fracture behavior of orthogonal woven fabric composite laminates has been examined. Crack propagation along the fill and weft yarns, respectively, was considere d for plain, twill and 8H-satin glass/epoxy composites, and a SH-satin carbon/epoxy composite. Fracture testing employed the mode I fracture DCB test specimen. Microscopic details of crack growth in the interpl y region were considered after fracture testing. The delamination resi stance and the difference in fracture toughness between the fill and w eft directions increased with increased weave index. Partial debonding of transversely oriented yams contributed to the delamination resista nce. Fracture of debonded fibers referred to as 'fiber bridging' was o bserved in the twill and satin weave glass/epoxy composites, but not i n the plain weave glass/epoxy and the SH-satin weave carbon/epoxy comp osites. The interlacing of the yarns limited the extent of fiber bridg ing. (C) 1998 Elsevier Science Ltd. All rights reserved.