Issue 52

S. Budhe et alii, Frattura ed Integrità Strutturale, 52 (2020) 137-147; DOI: 10.3221/IGF-ESIS.52.12

Tab. 2 summarizes the test results of 35 burst tests data using pipe specimens with machined different artificial metal losses (defects) [11, 19, 20, 24, 30-33] to demonstrate the suitability of the semi-empirical model for a better prediction of the strength capacity of defect pipe.

exp max P (MPa)

y  (MPa)

ult  (MPa) D (mm)

t (mm)

d (mm)

L (mm)

Sr. No (Ref.) Material Grade

1 [19] 2 [19] 3 [19] 4 [19] 5 [19] 6 [19] 7 [19] 8 [19] 9 [19]

X80 X80 X60 X46 A25 X60 X60 X60 X60 X60 X60 X60 X60 X80 X80 X42 X42 X46 X46 X46 X46 X46 X65 X65 X65 X65 X65 X65 X70 X60 X42 X42 X42 X42

589 601 452 391 260 452 452 452 452 452 452 452 452 601 589 380 380 495 495 495 495 495 495 305 478 284 284 284 284

731 684 542 458 309 542 542 542 542 542 542 542 542 684 731

459 457 324 76.2 76.2 324 324 324 324 324 324 324 324

7.9 7.9 9.5

3 4

40 40

24.2 22.7 14.4

6.67

256

2.04

1.4 1.4

75 75

9.4

2

5.45

9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 8.1 8.1

6.67 6.67 6.67 6.67 6.67 6.67 6.67 6.67 5.39 3.75 2.52 2.04 3.32 3.27 2.71 2.79 8.75 8.75 8.75 8.75 8.75 8.75 7.95 2.8

306 350 395 433 467 484 500 528 39.6

14.07 13.58 12.84 12.13 11.92 11.91 11.99 15.53 15.34 10.34 12.06 12.63 10.13 13.04 27.50 24.30 21.80 19.80 18.50 15.00 11.3 22.68 24.2

10 [19] 11 [19] 12 [19] 13 [19] 14 [30] 15 [30] 16 [20] 17 [20] 18 [20] 19 [20] 20 [20] 21 [20] 22 [20] 23 [31] 24 [31] 25 [31] 26 [31] 27 [31] 28 [31] 29 [32] 30 [33] 31 [11] 32 [24] 33 [24] 34 [24] 35 [24]

458.8 459.4 273.8 273.7 456.5 457.7 457.1 457.7 457.7 762.0 762.0 762.0 762.0 762.0 762.0

40.05 1000 1000 2750 2750 2750 2750 2750

528.5 528.5 458.2 539.2 557.3 428.5 568.2

5.30 5.24 6.56 6.23 6.09 6.04 6.03

357.9 355.7 362.3 285.1 345.4

565 565 565 565 565 565 585 542 464 464 464 464

17.50 17.50 17.50 17.50 17.50 17.50

50

100 200 300 600 900 300 133 500 49.7 49.8 69.7

532.2

628.8

762 219 527

15.9

21.2 13.8 11.6

Steel 20

6

3.6

14.3 5.80 5.60 5.55 5.62

10

60 60 60 60

4.1 3.5

54 61 46 44

4

4.5

50

Table 2: Burst tests data

B URST PRESSURE PREDICTION USING SEMI - EMPIRICAL MODELS igs. 2 and 3 present the ratio between the predicted burst pressure and the experimental burst pressure (P theoretical /P experimental ) using the different semi-empirical models. The results shows a mixed trend (conservative/non conservative/accurate) of burst pressure values between predicted and experimental with respect to the different semi empirical models. Some models show conservative predictions of burst pressure, while others F

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