Issue 49

E. Abdelouahed et alii, Frattura ed Integrità Strutturale, 49 (2019) 690-697; DOI: 10.3221/IGF-ESIS.49.62

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.

12 α (10 -6 °C)

12 α (10 -6 °C)

12 α (10 -6 °C)

E 1 (GPa)

E 2 (GPa)

E 3 (GPa)

G 12 (GPa)

G 13 (GPa)

G 23 (GPa)

12 γ

13 γ

23 γ

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

28

Pipeline Steel API 5L X70 , e pipe

= 4 mm = 2 mm

Composite Patch, e patch Adhesive FM 73, e a

= 0.2 mm Crack length a=5mm

26

24

22 K I ( MPa.m 0.5 )

20

Element type

C3D20R C3D15 C3D10

18

18000

19000

20000

21000

22000

23000

Number of nodes of structure

Figure 2 : Mesh convergence of the structure.

692