Issue 50

F. Larbi Chaht et alii, Frattura ed Integrità Strutturale, 50 (2019) 331-341; DOI: 10.3221/IGF-ESIS.50.28 339 These figures7-a-b-c show the effect of stacking on the resistance of these geometrically modified plates at the notch under the traction load. The catches are presented for each case and only for the damage of the fibers in tension which are responsible for the overall damage of the structure. For all cases of modification, we notice a linear behavior until the damage. For the simple geometry with the stacking effect we notice different values in the damage force as in the displacement at break. These stacks significantly improve the overall strength throughout the structure and particularly at the notch relative to the 0 and l orientation stacks. The stacks of 15 and 30 are more resistant than those of 45 and 60,which remain remarkable for the geometry of the first modification 1 with a different magnitude, except for the second modification which largely favors the stacking effect of all fiber orientation angles. In the end, we can see that with the geometric modifications and its optimized stacks we can obtain a higher resistance than the structures without modification. Figure 8: Reinforcement of the thickness of some layers (the modifications are symmetric in the other side). In this part of our study, we modified the mechanical properties of different layers by choosing a hybrid composite as shown in the following stacking sequences: (0/-30/30/90)s (0 R /-30/30/90)s (0/-30 R /30 R /90)s (0/-30/30/90 R )s where R stays for the reinforced thickness of layers in the composite. We change only the thickness of two layers which have the same fiber orientations for the three stacking sequences of structure (Fig. 8). Hence, we get 8 plies of composite. (a) (b) Figure 9: (a) Load displacement curve under tension loading of hybrid mod1. (b) Load displacement curve under tension loading of hybrid mod2.