PSI - Issue 14

M.K. Singh et al. / Procedia Structural Integrity 14 (2019) 475–481 M. K. Singh, R. Kitey / Structural Integrity Procedia 00 (2018) 000 – 000

480

Fig. 4. load vs. crosshead displacement curves of milled-fiber composites obtained by conducting quasi-static three-point-bend fracture tests on SENB specimens

The micrographs of fractured surface of the milled fiber reinforced epoxy composites are illustrated in Fig. 5. Evident of major toughening mechanism such as matrix cracking, fiber fracture, fiber pull out and fiber de-bonding could be seen from these images. Fig. 5 (a) represents the fracture surface of 1/8” fiber reinforced composite. From this figure it is observed that the hollow fiber footprint and emerging fiber segment from fractured surface numbered with 2,3,4,5 and 7 shows fiber pull out whereas 1,8 and 6 shows fiber fracture. Fig. 5(b) is a representative fractured surface of 1/4” fiber reinforced composites. Similar to 1/8” fibers reinforced case, the fiber numbered with 2,3 and 4 are the fractured fibers whereas fiber numbered with 1 shows fiber pull out. Furthermore, yellow arrow represents the direction of crack propagation and red arrow depicts the matrix cracking in both the micrographs.

(a)

(b)

50 µm

50 µm

4

7

3

3

1

2

6

1

2

4

5

8

Fig.5. Fractured surface micrograph of epoxy system reinforced with (a) 1/8” milled fiber (b) 1/4” milled fiber