PSI - Issue 5

Amr A. Abd-Elhady et al. / Procedia Structural Integrity 5 (2017) 123–130 Amr A. Abd-Elhady et al. / Structural Integrity Procedia 00 (2017) 000 – 000

128

6

3.4 Effect of composite repair on the progressive crack path

The effect of composite repair on crack growth and path of a stationary crack is shown in Fig. 5. The picture in each case has been taken after the crack path reached its steady state, i.e., at internal pressure equals P c . The steady state path of the growing crack is parallel to the pipe axis regardless of the inclination angle of the stationary crack. The composite repair has no effect on the crack path, as shown in Fig.5. The value of internal pressure of the pipe at stationary crack initiation, , P i , is shown in Fig. 5. It can be seen that the pipe with composite repair has a higher internal pressure value to initiate the stationary crack compared to the pipe without composite repair. Furthermore, the value of crack initiation internal pressure decreased with an increase in the value of crack angle. This means that, the most dangerous crack in the pipe subjected to internal pressure is the longitudinal crack.

With repair

Without repair



0 o

P i = 0.318262 MPa

P c = 0.31827 MPa

P i = 0.262329 MPa

P c = 0.26233 MPa

15 o

P i = 0.025031 MPa

P c = 0.02829 MPa

P i = 0.0197368 MPa

P c = 0.02489 MPa

45 o

P i = 0.0224373 MPa

P c = 0.28408 MPa

P i = 0.0163865 MPa

P c = 0.25532 MPa

75 o

P i = 0.021556 MPa

P c = 0.029311 MPa

P i = 0.0145091 MPa

P c = 0.025474 MPa

90 o

P i = 0.0206512 MPa

P c = 0.027013 MPa

P i = 0.0142894 MPa

P c = 0.023123 MPa

Fig. 5 The progressive crack path from inclined stationary crack in steel pipe based on XFEM