Issue 50

F. Larbi Chaht et alii, Frattura ed Integrità Strutturale, 50 (2019) 331-341; DOI: 10.3221/IGF-ESIS.50.28 337 fibers. The use of the Computer Aided Design Environment for Composites (CADEC 2014) will allow us in advantage to have the stiffness properties as well as the strength of the composite when loading at the notch. Effect of loading type and geometric modifications on the behavior damage of the laminate plate notching Often researchers are interested in structures that are subjected to loadings only in traction to determine their behavior. What is new in this part of the work is to add, not only another rarely studied behavior, but also to associate these two types of loading traction with rotation and likewise to make a comparison between these different types of loading in order to have a prediction of the damage of a notched laminate structure. First, each geometric model takes are evolution to the predicted damage that is presented by the load-displacement curves, these geometric models are: - simple model without modification, we took it as a witness in order to compare it with the other models those of renamed modifications 1 and 2. - for modification 1; we increased the thickness with the decrease in the volume fraction near the notch to keep the fiber continuity numerically. - for modification 2; it is the opposite of the modification 1, we decreased the thickness and increased the volume fraction in the vicinity of the notch. The proposition of these geometric shapes with the simple form allows us to better compare and better understand how the damage occurs in nonlinear (geometric and property) situations. Figure 5 shows the reaction of the structure to the imposed loading type traction and with circular notch. It can be seen that the effect of the proposed geometries is directly proportional to the strength of the structure; for geometric modification 1 where we have a reduction of the thickness at the notch which has a reduction which remains very small, the change of the load response of the structure appears beyond a displacement of 0.2mm. Modification 2 presents a whole change in the response to loading and subsequently in its resistance levels; less resistance more elongation in the structure. b) a) Figure 6: (a) Load displacement curve under torsion loading; (b) Load displacement curve under mixed loading. In the Figure 6-a, the proposed reinforcements not only increase the rigidity of the structure but also the resistance to damage. The proposed reinforcing capacity and in particular the modification 2 does not have any advantage in the resistance to damage. While the modification 1 is more resistant if and only if, the size of modification widens or is optimized, the same remarksare noted in the two types of loading applied; traction and torsion. On the other hand, what is different in the results is that the response to the loading for the behavior in torsion and purely linear with the fast damage. Figure 6-b shows the mixed stress of the notched plate: traction and rotation with the same pitch not to favor one over the other. It is also noted that the capacity of reinforcement by the proposed modifications on the structural resistance is conditioned much more by the type of loading than by the geometrical modifications.