Issue 49

E. Abdelouahed et alii, Frattura ed Integrità Strutturale, 49 (2019) 690-697; DOI: 10.3221/IGF-ESIS.49.62 692 least 10 elements at the front and near the crack tip. We have refined the mesh proportionally to the number of elements which gives the convergence of the results. We used quadratic elements based on quadratic interpolation functions in order to have a low calculation cost. A Gauss point is used per element which allows us to have a reduced integration scheme. Figure 1 : Diagram of a cracked aluminum pipe repaired by composite patch. E 1 (GPa) E 2 (GPa) E 3 (GPa) G 12 (GPa) G 13 (GPa) G 23 (GPa) 12 γ 13 γ 23 γ 12 α (10 -6 °C) 12 α (10 -6 °C) 12 α (10 -6 °C) API 5L X70 207 0.33 22.5 Adhesive (FM-73) 0.42 0.30 Bore/époxy 200 19.6 19.6 7.2 5.5 5.5 0.3 0.28 0.28 4.5 23 23 Glass/époxy 50 14.5 14.5 2.56 2.56 2.24 0.33 0.33 0.33 5.5 15 15 Carbone/époxy 134 10.3 10.3 5.5 5.5 3.2 0.33 0.33 0.53 -1.2 34 34 Table 1 : Elastic and thermal prosperity for different materials 18000 19000 20000 21000 22000 23000 18 20 22 24 26 28 K I ( MPa.m 0.5 ) Number of nodes of structure Element type C3D20R C3D15 C3D10 Pipeline Steel API 5L X70 , e pipe = 4 mm Composite Patch, e patch = 2 mm Adhesive FM 73, e a = 0.2 mm Crack length a=5mm Figure 2 : Mesh convergence of the structure.