PSI - Issue 5

Khodjet-Kesba Mohamed et al. / Procedia Structural Integrity 5 (2017) 271–278 Khodjet-Kesba Mohamed et al / Structural Integrity Procedia 00 (2017) 000 – 000

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Table 1. Material properties of composite used in calculations for glass/epoxy laminate (Berthelot 1997). E L (Gpa) E T (Gpa) G LT (Gpa) G TT (Gpa) ν LT V f 42.31 13.2 4.41 3.5 0.3 0.7

3.1. Variation of longitudinal stress along the laminate

The variation of longitudinal stress in the 90° layer along the laminate [0/90] S is shown as a function of the longitudinal coordinate (Fig. 2). For large crack density, the propagation of cracks cannot take place and this is justified by the saturation status. At the crack plane (X/l=1), the longitudinal stress decreases and vanishes. The results deduced from the complete parabolic shear-lag analysis are in good agreement with the finite element results. The other analytical models all moves further away as the crack density becomes higher.

1,2

Finite elements Parabolic analysis Progressive shear Variational model

1,0

0,8

0,6

 xx /  90

0,4

0,2

0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 0,0

X/l

Fig. 2. Variation of longit udinal stress σxx along the length of [0/90] S laminates with a=2.5 and Vf=0.7

3.2. Variation of interlaminar shear stress along the laminate :

0,6

Finite Elements Parabolic analysis Progressive shear Variational model

0,5

0,4

0,3

 (x)/  c

0,2

0,1

0,0

0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 -0,1

X/l

Fig. 3. Variation of interlaminar shear stress τ along the length of [0/90] S laminates with a=2.5 and Vf=0.7