Issue 49

E. Abdelouahed et alii, Frattura ed Integrità Strutturale, 49 (2019) 698-713; DOI: 10.3221/IGF-ESIS.49.63 701 Composite tubular structures having the following dimensions: a diameter equal to 50 mm and a thickness equal to 2 mm. The three elbows have the same radius of curvature equal to 20mm. Only one elliptical defect shape with one dimension is taken for each case. In order to better compare the damage results, these elbows are uniformly subjected to an imposed rotational movement of 60 ◦. In order to cause only the damage, the defect is always in these three locations in the extrados of the elbow Fig. (5). Figure 2 : Schematic representation of flexure moment in (a) in-plane closing moments, (b) in-plane opening moments reverse ovalization, and (c) out-of-plane bending For all the situations studied, the loading conditions are as follows: the attachment is always the same at the end of the linear part of the tube. This consists in fixing the three displacements following (x, y and z) and in the other end of the linear part of the tube, a rotation according to the studied case in the direction of opening or closing of the elbow. This rotation takes place around the plane of the structure until its damage, except for the case of moment out plans. It is reported that all the structures studied are under pressure with the presence of temperature in the form of a flow passing through the structure. The properties of the carbon / epoxy are chosen from the experimental work of Auwal Muhammad [32], which allowed us to use these stiffness and resistance parameters. These parameters characterize the architecture of a composite with a 45° crossover fabric orientation and with helical advancement along the longitudinal axis of the elbow and the straight portions. E 1 = 170000MPa ν 12 = 0.342 G 12 = 4800MPa X T =2050 Y T =62 α 11 =0.1x10 -6 K -1 E 2 = 9000MPa ν 13 = 0.342 G 13 = 4800MPa X C = 1200 Y C =190 α 22 =0.1x10 -6 K -1 E 3 = 9000MPa ν 23 = 0.342 G 23 = 4500MPa S L =81 S T =81 α 33 =0.1x10 -6 K -1 Table 1 : For a volume fraction of 65% E: Young’s modulus, ν: Poisson’s ratio, G: shear modulus, αII: orthotropic expansion [33] XT: Longitudinal tensile strength, XC: Longitudinal compressive strength, YT: Transverse tensile strength YC: Transverse compressive strength, SL: Longitudinal shear strength, ST: Transverse shear strength Figure 3 : Architecture and Schematizations of the local marks for the composite used [31]. The properties resulting from the experimental used by Auwal Muhammad [32], are for a straight tube. However, for the composite architecture at the elbow, it was provided by a local landmark that follows the curvature of the elbow. To evaluate