PSI - Issue 14

K. Chawla et al. / Procedia Structural Integrity 14 (2019) 571–576 K.Chawla et al./ Structural Integrity Procedia 00 (2018) 000 – 000

575

5

(b)

(a)

Fig. 3. Representative G I plots for (a) neat and (b) reinforced specimens.

Table 1.Fracture toughness ( G IC ) values obtained for neat and reinforced specimen.

Number of samples tested

2 )

2 )

G

G Ii (J/m

Specimen type

IC (J/m

Neat epoxy laminate

15 15

622 ± 9.30 815 ± 5.36

836 ± 12.87

Reinforced epoxy laminate

1001 ± 13.43

4. Conclusions Double cantilever beam tests are conducted to study the influence of short fibers on the interlaminar fracture behaviour of unidirectional woven glass fibre reinforced epoxy composites. Laminates are prepared by hand lay-up method. Two different epoxy systems, neat and 2% short fibers reinforced, are used as matrix material for coating the fiber cloth. Significant fibre bridging is observed in the presence of short fibres in the laminate which in-turn increased the resistance to interlaminar crack growth. Modified beam theory method is used for determining strain energy release rate ( G I ). The critical strain energy release rate ( G IC ) is caluclated to be ~ 836 J/m 2 and 1000 J/m 2 , for the neat and filler reinforced laminates, respectively. Johnson, W. S., Mangalgiri., P. D., 1986. Investigation of fiber bridging in double cantilever beam specimens. NASA . Huang, X. N., Hull., D. 1988. Effects of fibre bridging on G IC of a unidirectional glass/epoxy composite. Composite Science and Technology , 35:283 – 299. Sela, N., Ishai., O. 1989. Interlaminar fracture toughness and toughening of laminated composite materials: a review. Composites , 20:423 – 435, S. Spearing, M., Evans., A. G., 1992. The role of fibre bridging in the delamination resistance of fiber-reinforced composites. Acta Metall. mater. 40:2191 – 2199. Ebeling, T., Hiltner, A., Baer, A., Fraser, M., Orton., M.L. 1997. Delamination failure of a woven glass fibre composite. Journal of Composite Materials , 31:1318 – 1333. Arai, M., Noro, Y., Sugimoto, K., Endo., M. 2008. Mode I and mode II interlaminar fracture toughness of CFRP laminates toughened by carbon References