Issue 49

E. Abdelouahed et alii, Frattura ed Integrità Strutturale, 49 (2019) 698-713; DOI: 10.3221/IGF-ESIS.49.63 700   13 2 2 2 2 2 12 22 33 22 33 23 22 33 2 2 2 23 23 23 12 1 failure 1 1 no failure 2 4 C C Y S Y S S S                                           (4) 5. Interlaminar tensile failure for σ 33 > 0 2 33 1 failure 1 no failure T Z             (5) 6. Interlaminar compression failure for σ 33 < 0 2 33 1 failure 1 no failure C Z             (6) The simulations made are more reliable through the use of shell elements because there is no interface between the folds or between the fibers and the matrix. The numerical computation parameters have been in agreement with the computational convergence, which allows us more to go towards the evaluation of the quality of defect. These defects are hardly supported by numerical calculations using other criteria. The parameters introduced in the ABAQUS calculation code are: ** MATERIALS ** *Material, name=Material-1 *Damage Initiation, criterion=HASHIN 2050.,1200., 62., 190., 81., 81. *Damage Evolution, 45., 45., 0.6, 0.6 *Damage Stabilization 0.003,0.003,0.003,0.003 *Elastic, CONSTANTS 170000.,9000.,9000., 0.34, 0.34, 0.34,4800.,4800.4500., *Expansion, 0.1E-6, 0.1E-6, 0.1E-6 3. Description of model geometry and material properties The geometries of the composite structure with these standardized dimensions [31] are illustrated in Fig. (1). These characteristics of elasticity and resistance are reported in Tab.(1): The elbow element is connected to two straight pipes 1100 mm long. This length is sufficient to ensure that no stress interference in the region of the ends of the elbow will occur. It is assumed that no failure occurs at the straight pipe which should only act as a means of uniformly transferring the bending moments to the bends. Numerically the load of bending moment on the elbow was obtained by imposing a rotation about the axis perpendicular to the plane of curvature of the elbow. Figure 1 : Overview of the studied geometry.