Page 70 - Engineered Interfaces in Fiber Reinforced Composites

Chapter 3. Measurements of interfacelinterlaminar properties 53

Fig. 3.7. Schematic presentation of the applied fiber stress versus displacement (n - 6) curve in a fiber
pull-out test. After Kim et al. (1992).

characterization of these properties from experimental data will be discussed in
Chapter 5.
The fiber pull-out test has been widely used not only for polymer matrix
composites but also for some ceramic matrix (Griffin et al., 1988; Goettler and
Faber, 1989; Butler et al., 1990; Barsoum and Tung, 1991) and cement matrix
composites (see Bartos, 1981 for a useful review) as well as steel wire reinforced
rubber matrix composites (Ellul and Emerson, 1988a, b; Gent and Kaang, 1989).
However, this test method has some limitations associated with the scale of the test.
There is a maximum embedded length of fiber, L,,,, permitted for pull-out without
being broken. L,,, is usually very short, which causes experimental difficulties and

" mo 400 600
(a) Embedded fiber length, L(pm)

Fig. 3.8. Plots of interface bond strength, q,, versus embedded fiber length, L, (a) for a carbon fiber-epoxy
matrix system and (b) for a Hercules IM6 carbon fiber-acrylic matrix system. After Pitkethly and Doble
(1990) and Desarmont and Favre (1991).