Page 291 - Engineered Interfaces in Fiber Reinforced Composites

272 Engineered interfaces in fiber reinforced composites

(0/+45/0 1s o 2a/W=0,11
- A 0,24
E 0 0,32
E 0,42
4- " Ui 0 0,53
Y
Ln
A
E 3- '45 0,6 - A
Y 0
0 8
U 0,4-
2- A 'A
Au A
1- 0 0,2-
A

( 0/9012, o 2a/W= 0,14
A 0,21
0,35
0 0,45
-11 A 0.51
E
E
0
notch
I
H
U 90
5 A 0 OA
OA

I Ol I I "4 A I

Fig. 6.26. Subcrack lengths, &, and e,,, plotted as a function of K2 for different relative crack length,
2a/W (a) [O"/ f 45"/0"], laminates; (b) [0°/900],, laminates. After Ochiai and Peters (1982).

(Lhymn and Schultz, 1983). This observation is analogous to the fracture process in
the outer process zone which is termed the 'dissipation zone' as distinct from the
inner process zone ahead of crack tip (Lauke and Schultrich, 1986b; Lauke and
Pompe, 1988). In the dissipation zone, intensive energy dissipation by fiber-matrix
interfacial debonding and post-debonding friction is concentrated mainly at the fiber