Issue 48

A. S. Bouchikhi et al., Frattura ed Integrità Strutturale, 48 (2019) 174-192; DOI: 10.3221/IGF-ESIS.48.20 182 Case (2): In the following part, the AB crack is moved transversally near the notch of the crack CD see in Fig.8.b.This displacement has an effect on the J-integral as presented in Fig.11. It is observed it value at tip D is maximum when the transversal distance d=8 mm and the minimum value when d=0 mm; when d>0mm or d<8mm the effect of interaction vanishes completely and the J-integral at tips of CD crack is stabilized and becomes independent. -16 -12 -8 -4 0 4 8 12 16 20 4,0 4,2 4,4 4,6 4,8 5,0 5,2 5,4 5,6 J-Integral ( J/m 2 ) d(mm) Figure 11 : Variation of the J-integral at crack tip D versus distance d. The effect of transversal distance is also investigated for AB crack tips. This is illustrated in fig 12. From this figure the maximum J-integral values at tips A and B are attained when d tends to 2 mm. The minimum is obtained for d=-12mm and d=16mm at which the effect of interaction vanishes. Form Fig.11 we can see that the J-integral is critical at d=2mm where the effect is significant. -16 -12 -8 -4 0 4 8 12 16 20 0,0 0,5 1,0 1,5 2,0 J- Integral ( J/m 2 ) d(mm) Crack tip A Crack tip B Figure 12 : Variation of the J-integral at crack tip A and B versus distance d. Case (3): From the preceding studies treating the effect due the longitudinal displacement represented in Fig.8.c, the obtained results represented in Fig.13. The figure shows the J-integral variations with respect to the distance d between the crack tips. It is noticed the interaction effect is dependent on the distance d. When crack tip B approaches crack tip D. The J-integral at crack tip D increases exponentially. It is also observed a critical distance at d=16mm after which the J-integral is not stable. The interaction effect disappears completely. The effect of these cracks is determinant when they are closer to each other.