PSI - Issue 60

Thondamon V et al. / Procedia Structural Integrity 60 (2024) 484–493 Author name / StructuralIntegrity Procedia 00 (2019) 000 – 000

491

8

1000 1200 1400 1600 1800

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Load (kN)

ELTWCIN 24-3

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50

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Displacement (mm)

Fig. 6. Load-displacement of elbows with through-wall crack without internal pressure.

4. Results and discussion Three healthy elbows were tested, one with internal pressure and two without internal pressure, viz., PRELHO-8, ELHO-8 and ELHO-24-4 and their corresponding EMML values are 350 kN, 297 kN and 1905 kN respectively. For the elbow ELHO-24-4, test was terminated since the applied load was close to capacity of the actuator. From the experimental load-line displacement curves, using TES method, limit load were calculated for elbows PRELHO-8 and ELHO-8 as 110 kN and 117 kN. The limit load estimated by using the expressions of Chattopadhyay and Tomar (2006) for the elbows PRELHO-8, ELHO-8 and ELHO-24-4 are 124 kN, 113 kN and 2653 kN respectively. The limit load estimated by using the expressions of Chang-Sik and Kim (2006) are 101 kN, 113 kN and 2651 kN respectively. Similarly, the limit load estimated by using the expressions of Hong et al. (2010) are 106 kN, 113 kN and 2651 kN respectively. Table 5 summarises the limit load of healthy elbows. For healthy elbows, limit load from TES method are about one-third approximately as compared to EMML values. Expressions from all the three references considered for the study, predicted nearly the same limit load as the TES method for healthy elbows without internal pressure. For healthy elbows with internal pressure, limit load from TES method are about 10% less as compared to the limit load estimated by using Chattopadhyay and Tomar (2006) expressions and they are about 10% more as compared to the limit load estimated by using both Chang-Sik and Kim (2006) and Hong et al. (2010) expressions. Four elbows with circumferential through-wall crack at intrados were tested, three with internal pressure and one without internal pressure, viz., PRELTWCIN8-1, PRELTWCIN8-3, HPRELTWCIN8-1 and ELTWCIN-24-3 and their corresponding EMML values are 111 kN, 59 kN, 121 kN and 1579 kN respectively. Using the load displacement curves, TES method limit load were calculated for the corresponding elbows as 92 kN, 53 kN, 103 kN and 1549 kN respectively. The limit load estimated by using the expressions of Chattopadhyay and Tomar (2006) for the elbows are 63 kN, 28 kN, 52 kN and 1370 kN respectively. The limit load value estimated by using the expressions of Hong et al. (2010) are 75 kN, 39 kN, 61 kN and 1354 kN respectively. Table 6 summarises the limit load of elbows with circumferential through-wall crack at intrados. For elbows with circumferential through-wall crack at intrados, limit load from TES method are lesser than EMML values by 20%. For elbows with circumferential through-wall crack at intrados without internal pressure, limit load from TES method are about 10% more as compared to the limit load estimated by using the expressions of both Chattopadhyay and Tomar (2006) and Hong et al. (2010) expressions. Limit load estimated by using Chattopadhyay and Tomar (2006) expressions are marginally more than the limit load estimated by using Hong et al. (2010) expressions. For elbows with circumferential through-wall crack at intrados with internal pressure, limit