PSI - Issue 22

Yufei Li et al. / Procedia Structural Integrity 22 (2019) 43–50 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

47

5

4.2. Establishment of Finite Element Model for Premium connection The contact between the surfaces is realized by establishing contact pairs at the thread guide surface, the thread bearing surface, and the contact pairs at the sealing surface and shoulder surface. According to the setting principle of contact pairs, the thread guide surface, thread bearing surface and sealing surface - shoulder surface of the male buckle connection are set as slave surface. Since the male buckle connection has a relatively large rotation momentum compared with the female buckle connection, the slip property of the contact pair is set as a finite slip. The constraint on the end surface of the coupling is fixed. External loads are imposed by establishing continuous distributed node coupling. The simulated load table shown in Table 2 can be designed according to the test requirements of ISO 13679 CAL IV.

Table 2. Loads in series B test of ISO 13679 Load point

Bending degree/(°/(30m) -1 )

Axial load/kN

Internal pressure/MPa

1 2

— —

1203.65 1203.65

0

70.64 70.64 87.02 87.02 98.49 90.79 90.79 73.76 73.76 44.14 44.14

2B

19.7

1053

3

—

1013.6

3B

19.7

863.1

4 5

— —

544.81

0

5B

19.7

-150.47 -418.11 -267.64 -848.89 -698.39 -1203.65

6

—

6B

19.7

7

—

7B

19.7

8 、 9

—

0

5. Simulation results of sealing performance of premium connection 5.1. Results of sealing performance of premium connection for ISO 13679 B series test

Fig. 6 is the Von Mises stress of connection at critical load points in ISO 13679 B series test when bending loads are applied. There are stress concentrations in thread section and sealing surface. The state of the connection is tension on one side and compression on the other side; The Von Mises stress on the coupling near the sealing surface on the tension side is smaller. The Von Mises stress is greater at the end of the tubing. The Von Mises stress increases in the first quadrant along the loading path, whereas decreases in the second quadrant.

(a)Point of load 2B

(b) Point of load 3B