Page 208 - 3D Fibre Reinforced Polymer Composites

Stitched Composites 197

25 30E 3 stitches/cm* A
Unstitched

h A 6stitches/cmz

c

Impact Energy (J/mm)
Figure 8.30 Effect of very low energy impact loading on the amount of delamination
damage caused to an unstitched glass/vinyl ester composite and the same material
stitched with Kevlar yarn.

175 -
. Unstitched
150 - 2 stitchedcm'
E
E 125 - A 4 stitcheslcm'
v

0 2 4 6 8 10 12
Impact Energy (J/mm)

Figure 8.31 Effect of low energy impact loading on the amount of delamination damage
caused to stitched and unstitched composites (Data from Wu and Liau, 1995).